Butanoic acid synthesis

Butane, 2,3-0-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)-catalyst in homogeneous asymmetric hydrogenation, 6, 781 Butane-1,4-dioic acid, 2,2-di(indolyl)-synthesis, 4, 226 Butanenitrile, 4-hydroxy-dihydropyran synthesis from, 3, 769 Butanoic acid, -y-aryl-y-amino-synthesis, 1, 433 1-Butanol... 

A reaction by Clough et al. comes close to the direct synthesis shown in Scheme 1 (89TL7469). Here amides (62) react in a radical mechanism to 4-methylene compounds (63) that with 03/PPh3 are converted to tetramic acids (64). (See Fig. 29.) Several authors, however, prepared esters of 4-amino-3-oxo-butanoic acid, which served as precursors for intramolecular cyclization to tetramic acids (82JHC883). Koehler and Gerlach in an initial stage of a synthesis of dysidine, contained in marine sponge... 

Recently, we [67] have described the reduction of the methyl ester of 4-chloro-3-oxobutanoic acid (39) to the methyl ester of S-( )-4-chloro-3-hydroxy-butanoic acid (40) (Fig. 13) by cell suspensions of Geotrichum candidum SC 5469., S ( )-(40) is a key chiral intermediate in the total chemical synthesis of a cholesterol antagonist (SQ 33600), which acts by inhibiting hydroxymethylglu-taryl CoA (HMG CoA) reductase. In the biotransformation process, a reaction... 

The chiral monodeuterated ethanols 28 and 33 were obtained by Simon s method [33] and their tosylates, 29 and 34, reacted with malonic ester anion to afford 30 and 35. The expected inversion of configuration in the malonic ester synthesis was confirmed by decarboxylating the derived acids 31 and 36 to (35)- and (3R)-[3-2H,]butanoic acids, respectively, the chiroptical properties of which were already known [34]. The chirally deuterated CoA esters 32 and 37, prepared from 31 and 36, were rearranged on methylmalonyl-CoA mutase from P. shermanii and, after hydrolysis, the methylsuccinate products were isolated. In a parallel experiment the... 

Methyl-lf/-indol-l-yl)butanoic acid 135 easily prepared from 3-methylindole and dihydro-2(3//)-furanone, was used in the synthesis of natural 12//-pyrido[l,2- 7 3,4-/ ]diindoles which have antimicrobial activity and are cytotoxic against L-1210 mouse leukemia (Equation 25) <1996TL5207>. 

There are two major routes to phenanthrene, both of which can be used to prepare substituted derivatives. In the Haworth synthesis (Scheme 12.11), reaction of naphthalene with succinic anhydride yields an oxobut-anoic acid which is reduced under Clemmensen conditions to the butanoic acid. Cyclization in sulfuric acid and reduction of the resulting ketone is followed by dehydrogenation over palladium-on-carbon to phenanthrene. Alkyl or aryl derivatives can be obtained by treatment of the intermediate ketone with a Grignard reagent prior to dehydration and oxidation. 

The synthesis of 2-butanoic acid (CH3CH2CH2COOH) from diethyl malonate illustrates the basic process ... 

Dihydro-4 f-l,2,5-oxadiazines (21) (see Section 6.15.6.2.3.1) have been used as masked acyl groups for the stereoselective synthesis of 3(a)-(l-hydroxyethyl)-4( )-benzoyl- -lactams (24) (Scheme 2) <88EUP265169>. Condensation of the oxadiazine (21) with (2R,3R)-epoxy-butanoic acid in the presence of dicyclohexylcarbodiimide yields the A(-acyl derivative (22), which on treatment with lithium bis(trimethylsilyl)amide in THE undergoes stereoselective ring closure to the fused azetidinone (23). Hydrolysis with 1 M sulfuric acid in acetone ruptures the oxadiazine ring and forms the -lactam (24). 

The hydroformylation and amidocarbonylation of esters of methylvinylphosphinic acid have been studied in relation to the synthesis of probably the best known molecule t)f the types under consideration, viz. 2-amino-4-(hydroxymethylphosphinyl)butanoic acid, (398), also known as phosphinothricin or glufosinate. The outcome of the hydroformylation of the ester (401) depends on the nature of the catalyst employed. Thus the u.se of Rh (CO)j2. Rh2Cl2(CO)4, or HRh(CO)(PPh )2, leads to relatively high total yields of (402) and (403) but with low selectivity in contrast, when Co2(CO)j is employed, high selectivity with relatively low total yields are observed. Reactions in methanol afford a 90% relative yield of (402), Subsequent amidocarbonylation using the... 

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