Abstract: A novel method for preparing (+)compactin and (+)mevinolin analog compounds having a &bgr;-hydroxy-&dgr;-lactone grouping is disclosed. The method for preparing said compounds uses novel reaction intermediates. Said reaction intermediates and the respective methods for preparing same are also disclosed.

Abstract: The present application relates to novel compounds of the benzo-heterocycle family as well as to processes for their preparation and to the intermediate compounds obtained.

Abstract: Process for the stereospecific synthesis of leukotriene B.sub.4 (LTB.sub.4) of 6Z, 8E, 10E configuration of formula ##STR1## in which a dibenzoate triether is prepared which is subjected to a reductive elimination according to the diagram ##STR2## so as to obtain a triether which is converted in order to obtain the leukotriene B.sub.4.

Abstract: Propenals of formula: ##STR1## in which formula R is H or a C.sub.1 -C.sub.4 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.

Abstract: The invention relates to a stereospecific derivative of formula: ##STR1## in which R is hydrogen or a C.sub.1 -C.sub.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.

Abstract: The invention relates to a process for the manufacture of 6-trans-leukotriene B.sub.4 (LTB.sub.4) of formula ##STR1## in which a butadienediol is prepared; the hydroxyl groups are esterified to produce a diester and this diester is subjected to a stereospecific reductive elimination using low valency titanium [Ti(0)] to produce a 6-trans triether of formula: ##STR2## the groups --OA in positions 5 and 12 of which are then converted to --OH groups and the group --CH.sub.2 OA in position of which is then converted to a --COOH group, to produce 6-trans-LTB.sub.4.The invention also relates to intermediates obtained in the said manufacturing process.

Abstract: According to this process, one effects a stereospecific reduction of the two hydroxyl groups of an ether-diol by a mixture (titanium trichloride, lithium aluminum hydride) at a temperature between 5.degree. C. and about 40.degree. C. and that optionally, one converts the resulting ether into vitamin A, retinol or retinoic acid.Application to the synthesis of all-trans compounds selected from the group consisting of vitamin A and its ethers, retinol and retinoic acid, and their 13-cis isomers.

Abstract: Compounds, and a process for their preparation, have the formula ##STR1## or corresponding salts thereof wherein R represents a group of the formula ##STR2## wherein R.sub.1 represents oxazolinyl, --C.tbd.N, --CH.sub.2 OR.sub.2 or ##STR3## These compounds in the form of pharmaceutical or cosmetic compositions are useful for the treatment of keratinization disorders.