| 摘要 |
<p>New tritium-labelled steroids are cpds. of formula (I) in which R1 is lower alkyl; X is R2 being H or acyl; xx indicates the presence of tritium atoms in the 15- and 16-positions; Y is O a gp. convertible into O by hydrolysis, or a gp. H or OR3, R3 being H or acyl; and rings A and B have a 4,5- or 5,10-double bond when Y is O or the gp. H, OR3, or have a double bond terminating at the 5-position and also opt. a double bond terminating at the 3-position when Y is a gp. convertible into O by acidic hydrolysis. (I) are the (15,16)-tritiated derivs. of steroids which are used as contraceptives or are metabolites of contraceptive. they can be used as reagents or determn. of blood levels of the corresp. unlabelled cpds. by radioimmunoassay. The tritiated steroids (I) are chemically stable. Specific activities of ca. 57 Ci/mmol. can be reached, and the tritiated cpds. can be stored without loss of activity.</p> |
