Search PubMed⌕ Search

Biomedical subjects

W S Johnson

Publications and source records attributed to W S Johnson.

At least 37 records · Page 2Linked to original sources
PubMed1975

Morbidity and mortality in pseudopolycythaemia.

A follow-up of 35 patients with pseudopolycythaemia showed that symptoms, high packed-cell volumes, and low plasma volumes persisted in most patients. The death-rate in these patients was six times greater than expected. Patients with pseudopolycythaemia are often regarded as having a good prognosis; however, this view should be revised in the light of these findings.

Adult↗
PubMed1970

Application of the chloro ketal Claisen reaction to the total synthesis of squalene.

A short, highly stereoselective (over 97%) synthesis of all-trans squalene is described. Starting with succinaldehyde, a tetraenedichlorodione having the complete squalene skeleton with the four internal trans olefinic bonds has been developed in four steps involving a sequence of two double Claisen rearrangements. Three simple operations convert this intermediate into squalene.

Methods↗
PubMed1969

Total synthesis of dl-19-nor-16,17-dehydroprogesterone.

dl-2-(7,11-Dimethyl-3,7,11 - trans,trans-dodecatrienyl)-3-methyl-cyclopent-2-enol was prepared by reduction of the corresponding ketone. This tetraenol, on treatment with trifluoroacetic acid, underwent stereoselective cyclization to give dl-3,17-dimethyl-A-nor-D-homoestra-3,16-diene. This tetracyclic material was readily converted, by oxidative cleavage to the bicyclic triketo aldehyde followed by a double aldol cyclization, into dl-19-nor-16,17-dehydroprogesterone.

Chemical Phenomena↗
PubMed1969

Total synthesis of the racemic form of the second juvenile hormone (methyl 12-homojuvenate) from the cecropia silk moth.

Methyl cis-10-epoxy-3,7,11-trimethyl-trans,trans-2,6-tridecadienoate has been stereoselectively synthesized in 12 steps starting from methyl trans-gamma-bromo-beta,beta-dimethylacrylate and 1-acetyl-1-methylcyclopropane. The final product proved to be identical with the second, less abundant juvenile hormone (methyl 12-homojuvenate) isolated from the Cecropia silk moth. The biological activities of the compound were evaluated in various insects.

Journal Article↗