Convenient syntheses of iso‐methyl‐branched long‐chain aliphatic aldehydes, known to contribute significantly to meat flavour

Abstract

Convenient syntheses of iso-methyl-branched long-chain aliphatic aldehydes, which are common meat flavour compounds, are described. The Grignard reaction of isoamyl or isobutylmagnesium bromide and ω-bromo-α-alkanols in the presence of a catalytic amount of dilithium tetrachlorocuprate gave iso-methylalkanols. The oxidation of the alkanols using sodium hypochlorite in the presence of a catalytic amount of 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-N-oxide (BzOTEMPO) gave the corresponding iso-methylalkanals in high yield.

Identification of the possible new odor-active compounds “12-methyltridecanal and its analogs” responsible for the characteristic aroma of ripe Gouda-type cheese

“…The following compounds were synthesized according to the literature procedures, of which the final oxidation step was modified using 2,2,6,6-tetramethylpiperidine-N-oxide (TEMPO) instead of 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-N-oxide (BzOTEMPO): 11-methyldodecanal, 10) 13-methyltetradecanal, 10) and 14-methylpentadecanal. 10) Compounds (Table 1) Nos. 1-6, 8-9, 12, 14-15, 18-19, 21, 23, 25-29, 31, 34, and normal long-chain aldehydes in the carbon range of 11-16 were obtained from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan); Nos.…”

Synthesis, metabolic stability and antiviral evaluation of various alkoxyalkyl esters of cidofovir and 9-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]adenine

“…To introduce methyl groups at the ω-1 carbon of the alkyl chain (e. g. 15M-HDP-CDV and 15M-HDP-( S )-HPMPA), we first synthesized the ω-1 methyl alkanols using Grignard reactions of isoamyl or isobutylmagnesium bromide and ω-bromo-α-alkanols as described previously by Yuasa et al 14 The alkanols were then converted to methansulfonates and treated with 1,3-propanediol or ethylene glycol to give a series of ω-1-methylalkoxyalkanols which were coupled to cyclic cidofovir or cyclic (S)-HPMPA using the Mitsunobu esterification reaction (Scheme 1). 15 Basic hydrolysis of the cyclic CDV and (S)-HPMPA diesters gave the target phosphonoesters.…”

“…Syntheses and characterization of compounds 1 , 4 , 7 , and 8 (Scheme 1) were previously reported by Kern et al 2 , Wan et al 15 , Beadle et al 24 , and Morrey et al 25 , respectively. Grignard coupling reactions between isoamyl or isobutyl magnesium bromide and ω-bromo-α-alkanols were carried out as described by Yuasa and Tsuruta 14 to provide 15-methyl-hexadecanol, 14-methyl-pentadecanol, 13-methyl-tetradecanol and 12-methyl-tridecanol.…”

Biotechnological Production of Methyl-Branched Aldehydes

“…Nevertheless, the concentrations of 1 in natural sources are generally very low. Even its chemical synthesis is comparatively complex and therefore not economical or uses environmentally unfriendly chemicals. , Although more convenient strategies have been published recently, chemically synthesized 1 may not be marketed as natural . Therefore, to the best of our knowledge, no natural 1 is available as a flavoring substance on the world market, and no biotechnological route toward 1 has been commercialized so far.…”

“…8,13 Although more convenient strategies have been published recently, chemically synthesized 1 may not be marketed as natural. 14 Therefore, to the best of our knowledge, no natural 1 is available as a flavoring substance on the world market, and no biotechnological route toward 1 has been commercialized so far.…”