Gabriel Saucy

New manzamine alkaloids from a sponge of the genus xestospongia

Abstract Manzamines E ( 2 ) and F ( 3 ) have been isolated as cytotoxic constituents of a sponge of the genus Xestospongia and the structures elucidated by the application of 2D-NMR tecniques and spectroscoplc comparison with manzamine A (1). Manzamine F was shown to be identical with keramamine B ( 4 ), the structure of which should therefore be revised as 3 .

6-Hydroxychroman-2-carboxylic acids: Novel antioxidants

Abstract6-Hydroxychroman-2-carboxylic acids (I) have been found to be effective antioxidants in animal fats, vegetable oils, and emulsion systems. Two new syntheses of these compounds have been developed. Structure-activity correlations for I with various substitutents at C2, C5, C7, and C8 in various test systems have been obtained. In addition, the homologous chroman acetic acids, which are also antioxidants, and a number of other derived compounds have been synthesized. The most effective antioxidant in this series is the tetramethyl compound I (R2=R5=R7=R8=CH3). This compound has activity which compares well with the better commercial antioxidants.

NEW APPROACHES TO THE SYNTHESIS OF CANTHAXANTHIN

Abstract The use of sulfur ylides for the chain extention of polyene aldehydes and ketones is described. This work resulted in an approach to synthesizing canthaxanthin via 2,6,6-trimethyl-2-cyclohexen-1-one. The use of a substituted trimethylcyclohexenone or α-ionone for the construction of a C 15 phosphonium salt and its condensation with a C 10 dialdehyde for the synthesis of canthaxanthin is also reported.

New results in the total synthesis of 19-norsteroids

Abstract Recent endeavors in the field of steroid total synthesis have led to several new approaches which utilize the principle of asymmetric induction. Important developments will briefly be reviewed, followed by a presentation of two novel routes to estrone. The first is based on the use of (—)-(5S)-5-hydroxy-9-oxodecanoic acid lactone which is transformed in several steps to d-(−)-estra-4.9-diene-3, 17-dione and thence to estrone. The second, altogether different route starts with (+)-(7aS)-7,7a-dihydro7a-methyl-1,5(6H)-indandione and involves the preparation of a 9,10- seco ACD-tricyclic intermediate and its conversion into d-(+)-estrone methyl ether.

NEW RESULTS IN THE TOTAL SYNTHESIS OF 19-NORSTEROIDS

Recent endeavors in the field of steroid total synthesis have led to several new approaches which utilize the principle of asymmetric induction. Important developments will briefly be reviewed, followed by a presentation of two novel routes to estrone. The first is based on the use of (—)-(5S)-5-hydroxy-9-oxodecanoic acid lactone which is transformed in several steps to d-(—)-estra-4,9-diene-3,17-dione and thence to estrone. The second, altogether different route starts with (+)-(7aS)-7,7a-dihydro-7a-methyl-1,5(6H)-indandione and involves the preparation of a 9,10-seco ACD-tricyclic intermediate and its conversion into d-(+)-estrone methyl ether.

X-Ray structure determination of 4R,8R-p-menth-1-en-9-ol p-iodobenzoate. Revision of the absolute stereochemistry of natural (+)-juvabione

The absolute stereochemistry of (+)-4R,8R-p-menth-1-en-9-ol was determined by single-crystalX-ray analysis, and natural (+)-juvabione shown to have the R,S-configuration.