Process for the manufacture of furan derivatives
AssigneeGivaudan-Roure Corporation
InventorUlrich Huber
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Abstract
The invention is concerned with a process for the manufacture of substituted furans which are, in particular, flavorants; thereby 4-hydroxy-2-yn-1-ones or acetals or ketals thereof are cyclized with nucleophilic S-compounds to 3-S-furans, whereby this 3-S atom can be optionally substituted, and the acetylene derivatives, the 4-hydroxy-2-yn-1-ones, can be optionally 1- and/or 4-alkyl or alkenyl substituted.
Claims7
A process for the manufacture of compounds of the formula ##STR9## wherein R.sup.1 and R.sup.2 signify hydrogen, C.sub.1-6 -alkyl or C.sub.2-6 -alkenyl and
- C represents a sulphur-containing radical, which process comprises, as a primary reaction, cyclizing a compound ##STR10## or an acetal or ketal thereof using a reagent III which contains at least one nucleophilic sulphur atom
- AB III
- wherein
- A=H.sup.+, NH.sub.4.sup.+, N(C.sub.1-6 -alkyl).sub.3 H.sup.+, an alkali metal cation, or an alkaline earth metal cation, and
- B=R.sup.4 --S.sup.-, SCN.sup.-, AS.sub.2 O.sub.3.sup.-, H.sub.2 N--C(.dbd.S)NH--, R.sub.5 --S(.dbd.O)O.sup.-, or R.sub.5 --S--S.sup.-,
- wherein
- R.sup.4 =H, C.sub.1-6 -alkyl, C.sub.2-6 -alkenyl, C.sub.2-6 -alkynyl, C.sub.1-6 -alkyl substituted by halogen, OH, SH, C.dbd.O, a C.sub.1-6 -carboxylic acid residue, a C.sub.1-6 -alkylcarboxylic acid derivative, C.sub.1-6 -acyl or optionally substituted acyl, and R.sup.5 =C.sub.1-6 -alkyl, aryl, or heteroaryl, and,
- if desired, converting the primary reaction product of the formula ##STR11## into a subsequent product of the formula ##STR12## wherein R=R.sup.4 ;
- or SR.sup.5 in which SR.sup.5 represents (i) S--C.sub.1-6 -alkyl optionally functionalized with halogen, hydroxy, SH, carbonyl or carboxyl, (ii) S-aryl or (iii) S-heteroaryl.
Compounds of the formula ##STR14## in which R.sup.1 and R.sup.2 each independently signify H, CH.sub.3 or C.sub.2 H.sub.5, except that R.sup.1 and R.sup.2 cannot both equal H.
Dependencies are inferred from the claim text.