Hinsberg Sulfone Synthesis I sulfonylquinol I Reaction I Chemical Reaction

O. Hinsberg, Ber. 27, 3259 (1894); 28, 1315 (1895).Formation of sulfonylquinol derivatives by addition of quinones to cold dilute aqueous solutions of sulfinic acids:Hinsberg Sulfone SynthesisR. M. Scribner, J. Org. Chem. 31, 3671 (1966); H. Ulrich et al., Houben-Weyl 7/3a, 661 (1977). Cf. Thiele Reacti...

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Hinsberg Synthesis of Thiophene Derivatives I carboxylic acids I Reaction I Chemical Reaction

O. Hinsberg, Ber. 43, 901 (1910).Formation of thiophene carboxylic acids from ?-diketones and dialkyl thiodiacetates:Hinsberg Synthesis of Thiophene DerivativesH. Wynberg, D. J. Zwanenburg, J. Org. Chem. 29, 1919 (1964); H. Wynberg, H. J. Kooreman, J. Am. Chem. Soc. 87, 1739 (1965); A. Birch, D. A. Crombie, Chem. Ind. 1971, 177; D. J. Chadwick et al.,...

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Chromium I Nozaki-Hiyama Coupling Reaction (Nozaki-Hiyama-Kishi Reaction) I Reaction I Chemical Reaction

Y. Okude et al., J. Am. Chem. Soc. 99, 3179 (1977); K. Takai et al., Tetrahedron Letters 24, 5281 (1983).Chromium chloride catalyzed redox additions or organic halides to aldehydes:Nozaki-Hiyama Coupling Reaction (Nozaki-Hiyama-Kishi Reaction)Use of nickel salts as catalyst: H. Jin et al., J. Am. Chem. Soc. 108, 5644 (1986); K. Takai et al., ibid....

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Hoch-Campbell Aziridine Synthesis I hydrolysis I Reaction & Chemical Reaction

J. Hoch, Compt. Rend. 198, 1865 (1934); K. N. Campbell, J. F. McKenna, J. Org. Chem. 4, 198 (1939).Formation of aziridines by treatment of ketoximes with Grignard reagents and subsequent hydrolysis of the organometallic complex:Hoch-Campbell Aziridine SynthesisK. N. Campbell et al., J. Org. Chem. 8, 99, 103 (1943); 9, 184 (1944); J. P. Freeman, Chem....

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Houben-Hoesch Reaction I Synthesis of acylphenols I Reaction & Chemical Reaction

K. Hoesch, Ber. 48, 1122 (1915); J. Houben, ibid. 59, 2878 (1926).Synthesis of acylphenols from phenols or phenolic ethers by the action of organic nitriles in the presence of hydrochloric acid and aluminum chloride as catalyst: Houben-Hoesch ReactionReviews: P. E. Spoerri, A. S. DuBois, Org. React. 5, 387 (1949); Thomas, Anhydrous Aluminum Chloride...

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Hofmann Degradation (Exhaustive Methylation) I Reaction & Chemical Reaction I pyrolysis

A. W. Hofmann, Ber. 14, 659 (1881).Formation of an olefin and a tertiary amine by pyrolysis of a quaternary ammonium hydroxide: Hofmann Degradation (Exhaustive Methylation)A. C. Cope, E. R. Trumbull, Org. React. 11, 317-493 passim (1960); K. W. Bentley, G. W. Kirby in Techniques of Organic Chemistry vol. IV, Pt. 2, A. Weissberger, Ed., Elucidation...

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Hofmann Isonitrile Synthesis (Carbylamine Reaction) I Reaction & Chemical Reaction

A. W. Hofmann, Ann. 146, 107 (1868); Ber. 3, 767 (1870).Formation of isonitriles by the reaction of primary amines with chloroform in the presence of alkali; the odor of the isocyanide is a test for a primary amine: Hofmann Isonitrile Synthesis (Carbylamine Reaction)P. A. S. Smith, N. W. Kalenda, J. Org. Chem. 23, 1599 (1958); M. B. Frankel et al.,...

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Hofmann Reaction I carboxylic amides I Reaction & Chemical Reaction

A. W. Hofmann, Ber. 14, 2725 (1881).Conversion of primary carboxylic amides to primary amines with one fewer carbon atom upon treatment with hypohalites or hydroxide via the intermediate isocyanate: Hofmann ReactionEarly review: E. S. Wallis, J. F. Lane, Org. React. 3, 267-306 (1949). Alternative reagents/strategies: S. Kajigaeshi et al., Chem. Letters...

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Hofmann-Löffler-Freytag Reaction I pyrrolidines I Reaction & Chemical Reaction

A. W. Hofmann, Ber. 16, 558 (1883); 18, 5, 109 (1885); K. Löffler, C. Freytag, ibid. 42, 3427 (1909).Formation of pyrrolidines or piperidines by thermal or photochemical decomposition of protonated N-haloamines:Hofmann-Löffler-Freytag ReactionM. E. Wolff, Chem. Rev. 63, 55 (1963); E. J. Corey, W. R. Hertler, J. Am. Chem. Soc. 82, 1657 (1960); R. Furstoss...

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Hofmann-Martius Rearrangement (Aniline Rearrangement) I Reaction & Chemical Reaction

A. W. Hofmann, C. A. Martius, Ber. 4, 742 (1871); A. W. Hofmann, ibid. 5, 720 (1872).Thermal conversion of N-alkylaniline hydrohalides to o- and p-alkylanilines: Hofmann-Martius Rearrangement (Aniline Rearrangement)H. Hart, J. R. Kosak, J. Org. Chem. 27, 116 (1962); Y. Ogata et al., Tetrahedron 20, 2717 (1964); J. Org. Chem. 35, 1642 (1970); G. F....

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Hofmann Degradation (Exhaustive Methylation) I Reaction & Chemical Reaction

A. W. Hofmann, Ber. 14, 659 (1881).Formation of an olefin and a tertiary amine by pyrolysis of a quaternary ammonium hydroxide: Hofmann Degradation (Exhaustive Methylation)A. C. Cope, E. R. Trumbull, Org. React. 11, 317-493 passim (1960); K. W. Bentley, G. W. Kirby in Techniques of Organic Chemistry vol. IV, Pt. 2, A. Weissberger, Ed., Elucidation...

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Hofmann Isonitrile Synthesis (Carbylamine Reaction) I Reaction & Chemical Reaction

A. W. Hofmann, Ann. 146, 107 (1868); Ber. 3, 767 (1870).Formation of isonitriles by the reaction of primary amines with chloroform in the presence of alkali; the odor of the isocyanide is a test for a primary amine: Hofmann Isonitrile Synthesis (Carbylamine Reaction)P. A. S. Smith, N. W. Kalenda, J. Org. Chem. 23, 1599 (1958); M. B. Frankel et al.,...

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Hofmann Reaction I carboxylic amides I hydroxide I Reaction & Chemical Reaction

A. W. Hofmann, Ber. 14, 2725 (1881).Conversion of primary carboxylic amides to primary amines with one fewer carbon atom upon treatment with hypohalites or hydroxide via the intermediate isocyanate: Hofmann ReactionEarly review: E. S. Wallis, J. F. Lane, Org. React. 3, 267-306 (1949). Alternative reagents/strategies: S. Kajigaeshi et al., Chem. Letters...

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Hofmann-Löffler-Freytag Reaction I Reaction & Chemical Reaction

A. W. Hofmann, Ber. 16, 558 (1883); 18, 5, 109 (1885); K. Löffler, C. Freytag, ibid. 42, 3427 (1909).Formation of pyrrolidines or piperidines by thermal or photochemical decomposition of protonated N-haloamines:Hofmann-Löffler-Freytag ReactionM. E. Wolff, Chem. Rev. 63, 55 (1963); E. J. Corey, W. R. Hertler, J. Am. Chem. Soc. 82, 1657 (1960); R. Furstoss...

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Hofmann-Martius Rearrangement (Aniline Rearrangement) Reaction & Chemical Reaction

A. W. Hofmann, C. A. Martius, Ber. 4, 742 (1871); A. W. Hofmann, ibid. 5, 720 (1872).Thermal conversion of N-alkylaniline hydrohalides to o- and p-alkylanilines:Hofmann-Martius Rearrangement (Aniline Rearrangement)H. Hart, J. R. Kosak, J. Org. Chem. 27, 116 (1962); Y. Ogata et al., Tetrahedron 20, 2717 (1964); J. Org. Chem. 35, 1642 (1970); G. F. Grillot...

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Advantages I Asymmetric Synthesis of Epoxides and Aziridines from Aldehydes and Imines

Organic Synthesis & Epoxides and AziridinesEpoxides and aziridines are strained three-membered heterocycles. Their synthetic utility lies in the fact that they can be ring-opened with a broad range of nucleophiles with high or often complete stereoselectivity and regioselectivity and that 1,2-difunctional ring-opened products represent common motifs...

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Asymmetric Epoxidation of Carbonyl Compounds I Darzens reaction

Organic Synthesis - Epoxides and AziridinesThere have been two general approaches to the direct asymmetric epoxidation of carbonyl-containing compounds (Scheme 1.2): ylide-mediated epoxidation for the construction of aryl and vinyl epoxides, and a-halo enolate epoxidation (Darzens reaction) for the construction of epoxy esters, acids, amides, and ...

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Stoichiometric Ylide-mediated Epoxidation I asymmetric epoxidation I synthesized aryl-vinyl epoxides

Organic Synthesis & Epoxides and AziridinesSolladié-Cavallo’s group used Eliel’s oxathiane 1 (derived from pulegone) in asymmetric epoxidation (Scheme 1.3). This sulfide was initially benzylated to form a single diastereomer of the sulfonium salt 2. Epoxidation was then carried out at low temperature with the aid of sodium hydride to furnish diaryl...

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Hofmann-Sand Reactions I alkoxyalkyl I Organometallic

Reaction & Chemical ReactionK. A. Hofmann, J. Sand, Ber. 33, 1340, 1353 (1900).Olefin mercuration with mercuric salts (halides, acetates, nitrates, or sulfates) in aqueous solution. In alcoholic solutions the accelerated reaction produces alkoxyalkyl compounds:Hofmann-Sand ReactionsJ. Sand, Ber. 34, 1385, 2906, 2910 (1901); Ann. 329, 135 (1903);...

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Hooker Reaction I Steyermark I hydroxy I methylene

Reaction & Chemical ReactionS. C. Hooker, J. Am. Chem. Soc. 58, 1174 (1936).Oxidation of 2-hydroxy-3-alkyl-1,4-quinones with dilute alkaline permanganate with shortening of the alkyl side chain by a methylene group and simultaneous exchange of hydroxyl and alkyl or alkenyl group positions:Hooker ReactionS. C. Hooker, A. Steyermark, J. Am. Chem....

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Synthetic applications I Sakurai Reaction (Hosomi-Sakurai Reaction) Organometallic

Reaction & Chemical Reaction:A. Hosomi, H. Sakurai, Tetrahedron Letters 1976, 1295; A. Hosomi et al., Chem. Letters 1976, 941.Lewis acid-promoted nucleophilic addition of allylic silanes to carbon electrophiles accompanied by regiospecific transposition of the allylic moiety:Sakurai Reaction (Hosomi-Sakurai Reaction)Synthetic applications: I. E....

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Acidic hydrolysis yields ketones - Houben-Fischer Synthesis

Reaction & Chemical ReactionJ. Houben, W. Fischer, J. Prakt. Chem. [2] 123, 89, 262, 313 (1929).Formation of aromatic nitriles by basic hydrolysis of trichloromethyl aryl ketimines. Acidic hydrolysis yields ketones.J. Houben, W. Fischer, Ber. 63, 2464 (1930); 64, 240, 2636, 2645 (1931); 66, 339 (1933); D. T. Mowry, Chem. Rev. 42, 221 (1948); P....

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Acylphenols - Houben-Hoesch Reaction - Chemistry

Reaction & Chemical ReactionK. Hoesch, Ber. 48, 1122 (1915); J. Houben, ibid. 59, 2878 (1926).Synthesis of acylphenols from phenols or phenolic ethers by the action of organic nitriles in the presence of hydrochloric acid and aluminum chloride as catalyst:Houben-Hoesch ReactionReviews: P. E. Spoerri, A. S. DuBois, Org. React. 5, 387 (1949); Thomas,...

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Chemical Technology I Houdry Cracking Process

oxide - Reaction - Chemical ReactionHoudry. Houdry Cracking ProcessE. Houdry, US 1957648 and US 1957649 (1934).Decomposition of petroleum or heavy petroleum fractions into more useful lower boiling materials by heating at 500° and 30 psi, over a silica-alumina-magnanese oxide catalyst.E. Houdry et al., Oil Gas J. 37, 40 (1938); A. N. Sachanen, Chemical...

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stereoselectivity I Asymmetric Synthesis of Epoxides and Aziridines from Aldehydes and Imines

Organic Synthesis & Epoxides and Aziridines:Epoxides and aziridines are strained three-membered heterocycles. Their synthetic utility lies in the fact that they can be ring-opened with a broad range of nucleophiles with high or often complete stereoselectivity and regioselectivity and that 1,2-difunctional ring-opened products represent common...

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Darzens reaction I Asymmetric Epoxidation of Carbonyl Compounds

Organic Synthesis & Epoxides and Aziridines:There have been two general approaches to the direct asymmetric epoxidation of carbonyl-containing compounds (Scheme 1.2): ylide-mediated epoxidation for the construction of aryl and vinyl epoxides, and a-halo enolate epoxidation (Darzens reaction) for the construction of epoxy esters, acids, amides,...

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Asymmetric epoxidation I Stoichiometric Ylide-mediated Epoxidation

Camphorsulfonyl hloride - Organic Synthesis - Epoxides and Aziridines :Solladié-Cavallo’s group used Eliel’s oxathiane 1 (derived from pulegone) in asymmetric epoxidation (Scheme 1.3). This sulfide was initially benzylated to form a single diastereomer of the sulfonium salt 2. Epoxidation was then carried out at low temperature with the aid of sodium...

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Alkoxyalkyl I Hofmann-Sand Reactions, alkoxyalkyl

Organometallic CompoundsK. A. Hofmann, J. Sand, Ber. 33, 1340, 1353 (1900).Olefin mercuration with mercuric salts (halides, acetates, nitrates, or sulfates) in aqueous solution. In alcoholic solutions the accelerated reaction produces alkoxyalkyl compounds:Hofmann-Sand ReactionsJ. Sand, Ber. 34, 1385, 2906, 2910 (1901); Ann. 329, 135 (1903); J. Chatt,...

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Chemical Reaction, Hooker Reaction, hydroxy, alkyl

Oxidation ofS. C. Hooker, J. Am. Chem. Soc. 58, 1174 (1936).Oxidation of 2-hydroxy-3-alkyl-1,4-quinones with dilute alkaline permanganate with shortening of the alkyl side chain by a methylene group and simultaneous exchange of hydroxyl and alkyl or alkenyl group positions:Hooker ReactionS. C. Hooker, A. Steyermark, J. Am. Chem. Soc. 58, 1179 (1936);...

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Wittig Reaction; Horner Reaction; Horner-Wadsworth-Emmons Reaction - phosphonium ylides

G. Wittig, U. Schöllkopf, Ber. 87, 1318 (1954); G. Wittig, W. Haag, ibid. 88, 1654 (1955).Alkene formation from carbonyl compounds and phosphonium ylides, proceeding primarily through the proposed betaine and/or oxaphosphetane intermediates. The stereoselectivity can be controlled by the choice of ylide, carbonyl compound, and reaction conditions:Wittig...

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Sakurai Reaction (Hosomi-Sakurai Reaction), regiospecific transposition

A. Hosomi, H. Sakurai, Tetrahedron Letters 1976, 1295; A. Hosomi et al., Chem. Letters 1976, 941.Lewis acid-promoted nucleophilic addition of allylic silanes to carbon electrophiles accompanied by regiospecific transposition of the allylic moiety:Sakurai Reaction (Hosomi-Sakurai Reaction)Synthetic applications: I. E. Markó, D. J. Bayston, Tetrahedron...

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Sakurai Reaction (Hosomi-Sakurai Reaction), regiospecific transposition

A. Hosomi, H. Sakurai, Tetrahedron Letters 1976, 1295; A. Hosomi et al., Chem. Letters 1976, 941.Lewis acid-promoted nucleophilic addition of allylic silanes to carbon electrophiles accompanied by regiospecific transposition of the allylic moiety:Sakurai Reaction (Hosomi-Sakurai Reaction)Synthetic applications: I. E. Markó, D. J. Bayston, Tetrahedron...

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Houben-Fischer Synthesis I Acidic hydrolysis yields ketones

J. Houben, W. Fischer, J. Prakt. Chem. [2] 123, 89, 262, 313 (1929).Formation of aromatic nitriles by basic hydrolysis of trichloromethyl aryl ketimines. Acidic hydrolysis yields ketones.J. Houben, W. Fischer, Ber. 63, 2464 (1930); 64, 240, 2636, 2645 (1931); 66, 339 (1933); D. T. Mowry, Chem. Rev. 42, 221 (1948); P. E. Spoerri, A. S. DuBois, Org....

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Houben-Hoesch Reaction, Synthesis of acylphenols

K. Hoesch, Ber. 48, 1122 (1915); J. Houben, ibid. 59, 2878 (1926).Synthesis of acylphenols from phenols or phenolic ethers by the action of organic nitriles in the presence of hydrochloric acid and aluminum chloride as catalyst: Houben-Hoesch ReactionReviews: P. E. Spoerri, A. S. DuBois, Org. React. 5, 387 (1949); Thomas, Anhydrous Aluminum Chloride...

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Houdry Cracking Process, Houdry, oxide catalyst

Houdry Cracking ProcessE. Houdry, US 1957648 and US 1957649 (1934).Decomposition of petroleum or heavy petroleum fractions into more useful lower boiling materials by heating at 500° and 30 psi, over a silica-alumina-magnanese oxide catalyst.E. Houdry et al., Oil Gas J. 37, 40 (1938); A. N. Sachanen, Chemical Constituents of Petroleum (New York, 1945)...

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Carbonyl, Wolff-Kishner Reduction; Huang-Minlon Modification "methyl"

N. Kishner, J. Russ. Phys. Chem. Soc. 43, 582 (1911), C.A. 6, 347 (1912); L. Wolff, Ann. 394, 86 (1912); Huang-Minlon, J. Am. Chem. Soc. 68, 2487 (1946).Complete reduction of carbonyl compounds to methyl or methylene groups on heating with hydrazine hydrate and a base. In the Huang-Minlon modification diethylene glycol is used as a solvent:Wolff-Kishner...

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Chemical, Pictet-Hubert Reaction Morgan-Walls Reaction, Morgan-Walls Reaction

A. Pictet, A. Hubert, Ber. 29, 1182 (1896); C. T. Morgan, L. P. Walls, J. Chem. Soc. 1931, 2447; 1932, 2225.Phenanthridine cyclization by dehydrative ring closure of acyl-o-aminobiphenyls on heating with zinc chloride at 250-300° (Pictet-Hubert), or with phosphorus oxychloride in boiling nitrobenzene (Morgan-Walls):Pictet-Hubert Reaction; Morgan-Walls...

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Hunsdiecker Reaction (Borodine Reaction), catalysis, Hunsdiecker, decarboxylation

Chowdhury, decarboxylationC. Hunsdiecker et al., US 2176181 (1939); H. Hunsdiecker, C. Hunsdiecker, Ber. 75, 291 (1942); A. Borodine, Ann. 119, 121 (1861).Synthesis of organic halides by thermal decarboxylation of silver salts of the corresponding carboxylic acids in the presence of halogensHunsdiecker Reaction (Borodine Reaction) R. G. Johnson, R....

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Hydroboration Reaction, hydrides, organoboranes, alkynes

Ohlmeyer, Adv. Chem, Suzuki Coupling, asymmetricH. C. Brown, B. C. Subba Rao, J. Am. Chem. Soc. 78, 5694 (1956); J. Org. Chem. 22, 1135, 1136 (1957).Addition of boron hydrides to alkenes, allenes, and alkynes to form organoboranes, such that boron adds to the less substituted carbon. Attack usually takes place on the less hindered side in a cis fashion:Hydroboration...

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Oxo Process (Hydroformylation Reaction), The process is sometimes carried out in two stages

Hydroformylation. Oxo Synthesis, Roelen ReactionO. Roelen, US 2327066 (1943); R. H. Hasek (Eastman), Org. Chem. Bull. 27, No. 1 (1955).Formation of alcohols from olefins, carbon monoxide and hydrogen in the liquid phase in the presence of catalysts (metallic cobalt compounds such as Raney cobalt or cobalt carbonyls) at 115-190° and high pressures (100-200...

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Focused ultrasound ablation, Skin burns, Back or leg pain, Nerve damage, Abdominal pain, Cramping, Nausea, Fever, Vaginal discharge, Urinary tract inf

KK Women's and Children's Hospital is now equipped with the new MR-guided Focused Ultrasound Ablation System, offering a non-invasive, effective and outpatient solution to treat uterine fibroids.The system, ExAblate 2000, has been highlighted by U.S. FDA as one of the 14 medically significant products it approved during fiscal 2005.What are Uterine...

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Medical Specialties & Service Center I Men I Women's Center, I pain urinary endometriosis menopause I hurt

Women's Pain Center Help for women to overcome the pain Location Level 1 (in KK Breast Center) Phone 6294 4050 (for appointments) 6394 8073 (for questions) E-mail womenpaincentre@kkh.com.sg Do not suffer in silence. We can take your pain, so you can enjoy life again. Their pain twice a month cycle of menstrual cramps? Or you dying...

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Medical Specialties & Services I Children's Hospital I Medical I Respiratory Medicine I Partners in Asthma Care I Druckansicht Druckversion

KKH Partners in Asthma Care Service of respiratory medicine KK Women's and Children's Hospital shortly KKH Partners in Asthma Care - a program for community and primary health care KKH specialists work together as a team and manage child asthma conditions.Under this program, children with asthma are relatively stable, are becoming the family doctor...

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