90846-70-1Relevant academic research and scientific papers
PROCESS FOR SYNTHESIS OF PICOLINAMIDES
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Paragraph 0239, (2021/04/23)
The present technology relates to processes, mixtures and intermediates useful for making picolinamide fungicides. The picolinamide compounds are prepared by processes that include coupling together a 4-methoxy-3-acyloxypicolinic acid with key 2-amino-L-alaninate esters derived from substituted 2-phenylethanols.
1,3-dioxolan-2-ylium cations from acylfurans: Conversion of furyl ketones to esters under nonoxidative conditions
Bender, John A.,Daves, Samantha,West
, p. 2051 - 2054 (2007/10/03)
Acylfurans 3 furnished tosylated glycol monoesters 5 when treated with 1,2-diols in the presence of an equivalent of TsOH. This process likely occurs via protiodefuranation of the intermediate furyl ketals to form 1,3- dioxolan-2-ylium cations 8. Subsequent ring-opening via S(N)2 nucleophilic displacement by p-toluenesulfonate then provides esters 5. When a 1,3-diol was employed, furancontaining ester 9 was formed instead of the standard product through an apparent aldol dimerization/fragmentation pathway.
SYNTHESIS OF OPTICALLY PURE COMPOUNDS BY ENANTIOTOPICALLY DIFFERENTIATING MONOACETALIZATION OF PROCHIRAL DIKETONES. PART II. FRAGMENTATION OF β-KETO-ACETALS
Duthaler, Rudolf O.,Maienfisch, Peter
, p. 832 - 844 (2007/10/02)
Treatment of β-keto-acetals, derived from non-enolisable β-diketones, with sulfonic acids in boiling benzene results in a smooth retro-Claisen-type fragmentation.The acetal-C-atom is thereby transformed into a carboxylic ester via a dialkoxycarbenium ion, which is dealkylated by the sulfonate counter-ion.Application of this reaction to the diastereomeric monoacetals 3 and 4, derived from cis-9-methyl-decalin-1,8-dione (1), followed by transesterification with CH3OH, yields optically pure 4-(2'-methyl-3'-oxocyclohexyl)butyrate 9 ((+)-9 from 3, (-)-9 from 4) and the monosulfonate of meso-2,3-butanediol (-)-13 (Scheme 2).Unexpected, this cleavage proceeds as well with monoacetal 26, obtained by acetalization of trans-9-methyl-decalin-1,8-dione (27) with 2,2-dimethyl-1,3-propanediol (Scheme 7).Some attempts, aiming at an isomerization of the cis- and trans-decalin derivatives 3 and 24, or 25 and 26, via the postulated carboxonium intermediate, were not successful.
