Arndt

Arndt-Eistert synthesis A procedure for converting a carboxylic acid to its next higher homologue, or to a derivative of a homologous acid, e.g. ester or amide. 

Sauer T, Arndt T, Batchelder D, Kalachev A A and Wegner G 1990 The structure of Langmuir-Blodgett-films from substituted phthalocyaninato-polysiloxanes Thin Solid Films 187 357-74... 

The Arndt-Eistert reaction is a comparatively simple method for converting an acid Into its next higher homologue or to a derivative of the homologous acid, such as an amide or an ester. The overall yield is generally good. The reaction... 

Alkyl groups attached to aromatic rings are oxidized more readily than the ring in alkaline media. Complete oxidation to benzoic acids usually occurs with nonspecific oxidants such as KMnO, but activated tertiary carbon atoms can be oxidized to the corresponding alcohols (R. Stewart, 1965 D. Arndt, 1975). With mercury(ll) acetate, allyiic and benzylic oxidations are aJso possible. It is most widely used in the mild dehydrogenation of tertiary amines to give, enamines or heteroarenes (M. Shamma, 1970 H. Arzoumanian. 1971 A. Friedrich, 1975). 

Selective oxidation of secondary alcohols to ketones is usually performed with CrOj/HjSO, I I in acetone (Jones reagent) or with CrOjPyj (Collin s reagent) in the presence of acid-sensitive groups (H.G. Bosche, 1975 C. Djerassi, 1956 W.S. Allen, 1954). As mentioned above, a,)S-unsaturated secondary alcohols are selectively oxidized by MnOj (D.G. Lee, 1969 D. Arndt, 1975) or by DDQ (D. Walker, 1967 H.H. Stechl, 1975). 

D. Arndt, Manganese Compounds as OxidifingMgents in Organic Chemisty, Open Court Publishing Co., LaSalle, IU., 1981, pp. 169—177. 

E. Schritder, G. MbUer, and K.-E. Arndt, Polymer Characteri tion Hanser PubHsher, New York, 1989, p. 94. 

Werner Engewald. Therese Koal, Arndt Asperger, Jurgen Efer... 

ARNDT EISTERT Homoiogation Homologalion of carboxylic acids or ketones... 

The methods for preparing methyl mercaptan and /3-hydroxy-ethyl methyl sulfide are essentially those of Arndt and Kirner, respectively. 

Phenoxybutyric acid [6303-58-8] M 180.2, m 64", 65-66", 82-83", 99", b 180-185"/ 2mm, pK 3.17. It has been purified by recrystn from pet ether, C6H6, Et20-pet ether, EtOH and from H2O. It can be steam distd or distd in a good vac. [UV Ramart-Lucas and Hoch Bull Soc Chim Fr [4] 51 824 1932, Dann and Arndt Justus Liebigs Ann Chem 587 38 1954.] The acid chloride has b 154-156°/20mm [Hamford and Adams J Am Chem Soc 57 921 1935], and the amide crystallises from C6H6 as needles m 113°. 

Organometallics, such as dialkyl zinc or cadmium-alkyl or aryl lithium Alkali acetylides Diels-Alder Arndt-Eistert... 

Arndt-Eistert reaction is used to convert an acid compound into the next higher homologue by reaction with diazomethane... 

Arndt, F. Thesis, Medizinisches Zentrum fiir Klinische Chemie und Fachhochschule Gieflen, 1983. 

The position of the keto group of A-homo-5a-cholestan-3-one (5b) was determined by Nelson and Schut by an unambiguous synthesis of ketone (5b) involving bis-homologation of 2,3-seco-5a-cholestane-2,3-dioic acid (8) using the Arndt-Eistert sequence [(9) (11)]. 

Bohlmann and Arndt (S3) have separated the possible stereoisomers of hexahydrojulolidine (78-80) and subjected them to mercuric acetate oxidation. The rates, which were followed by the precipitation of mercurous acetate, showed that isomer 78 reacted about five times faster than isomer 79, while isomer 80 reacted very slowly. The difference in rates between 78 and 79, both of which have tertiary a-hydrogens trans to the nitrogen electron pair, was explained by pointing out that greater relief of non-classical strain occurs in the oxidation of 78 as compared to 79. Isomer 80 has no tertiary a-hydrogens trans to the nitrogen electron pair except when it is in an unfavorable boat conformation. 

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