- A convenient high yield synthesis of functional methacrylates via dethioacetalization. Synthesis of methacrylate S,S-acetal derivatives as intermediates
-
We describe a selective and efficient synthesis of a whole new class of functional methacrylates starting from S,S-acetals. Carbonyl compounds were regenerated from corresponding S,S-acetaIs using mercury (II) salts. According to this method, methacrylic
- Caye, Florence,Sindt, Michele,Mieloszynski, Jean-Luc,Paquer, Daniel
-
p. 197 - 220
(2007/10/03)
-
- Enantioselective preparation of 2-substituted-1,3-dithiane 1-oxides using modified Sharpless sulphoxidation procedures
-
Enantioselective sulphoxidation of a wide range of 2-substituted-1,3-diathianes has been carried out using modified Sharpless conditions to furnish the corresponding sulphoxides in optically enriched form. Deacylation of 2-acyl-1,3-dithiane 1-oxide deriva
- Page, Philip C. Bulman,Wilkes, Robin D.,Namwindwa, Ernest S.,Witty, Michael J.
-
p. 2125 - 2154
(2007/10/03)
-
- Compositions of retinoids substituted with a dithiane ring, their use, and process for preparing the compounds
-
The invention relates to a stereospecific derivative of formula: STR1 in which R is hydrogen or a C 1 -C 4 thioalkyl. The invention also relates to the use of these compounds for the manufacture of stereospecific retinal or retinoic acid, as well as to a process for preparing the retinoids of formula (I). The invention finally relates to a cosmetic or pharmaceutcial composition which contains at least one compound of formula (I) in a suitable vehicle; the pharmaceutical composition according to the invention may be used for treating dermatological, rheumatic, respiratory or ophthalmological conditions.
- -
-
-
- Propenals substituted with a dithiane ring and processes for the preparation of these propenals
-
Propenals of formula: STR1 in which formula R is H or a C1 -C4 thioalkyl radical, the dithiane ring being at the cis position in relation to the aldehyde function when R is H and at the trans position when R is a thioalkyl radical. The invention also relates to two processes for the preparation of these propenals.
- -
-
-
- Reactions of δ-valerolactone with lithio trithio-orthoformates
-
δ-valerolactone (3), on treatment with tris(methylthio)methyllithium (7) followed by weakly acidic aqueous work-up, gave a tautomeric mixture of 1,1-bis(methylthio)-6-hydroxy-2-hexanone (8a) and tetrahydro-2-bis(methylthio)methyl-2-pyranol (8b).Under analogous conditions 3 reacted with tris(phenylthio)methyllithium (10) to form tetrahydro-3-(phenylthiocarbonyl)-2-pyranone (11).With 2-(methylthio)-1,3-dithian-2-yllithium (16) it gave a tautomeric mixture of 2-(5-hydroxy-1-oxopentyl)-2-(methylthio)-1,3-dithiane (17a) and 2-(tetrahydro-2-hydroxy-2-pyranyl)-2-(methylthio)-1,3-dithiane (17b).Treatment of 17 with methanol in the presence of acidic ion-exchange resin gave a mixture of 2-(5,6-dihydro-3-(methylthio)-2(4H)-pyranyl-1,3-dithiane (20), 2-(tetrahydro-2-methoxy-2-pyranyl)-1,3-dithiane (21), and 2-(tetrahydro-2-methoxy-(4-methylthio)-2-pyranyl)-1,3-dithiane (22).Similar treatment of 20 gave a mixture of 20, 21, and 22.Compound 21 was synthesized independently by similar treatment of 2-(tetrahydro-2-hydroxy-2-pyranyl)-1,3-dithiane (23).The origins of the anomalous products are discussed briefly.It is concluded that because of these anomalies the preparation of tetrahydro-2-hydroxypyran-2-carboxylic acid acetals and related glycosides via trithio-orthoformate derivatives can encounter difficulties, although dithioacetales may serve this purpose. Key words: 1,3-dithianes, α-hydroxy acids, δ-lactones, trithio-orthoformates.
- Yates, Peter,Seif-El-Nasr, Azza,Stanton, Jennifer,Krepinsky, Jiri J.
-
p. 415 - 422
(2007/10/02)
-
- Synthesis of E Functionalized Prenyl Orthothioesters
-
A stereospecific route to (E)-3-2-methylpropenal 5 and to (E)-3-(4-methylthio-1,3-dithiane-2-yl)-2-methylpropenal 7 is described.
- Solladie, Guy,Berl, Valerie
-
p. 6329 - 6332
(2007/10/02)
-
- STUDY OF THE ANOMERIC EFFECT IN 2-SUBSTITUTED 1,3-DITHIANES
-
The conformational analysis of several 2-substituted 1,3-dithianes made possible the evaluation of S-C-Y anomeric interactions, where Y=SCH3,SC6H5,CO2CH3,COC6H5,CO2H and N(CH3)2.The relative magnitude of the effects observed for these groups odithiane(Y)-ΔGocyclohexane(Y)> can be explained in terms of the combined influence of dipole/dipole and two-electron stabilizing interactions (stereoelectronic effect).
- Juaristi, Eusebio,Tapia, Josefina,Mendez, Rodolfo
-
p. 1253 - 1264
(2007/10/02)
-