## Abstract A selective total synthesis of [11,12‐^3^H]‐9‐__cis__‐retinoic acid 1 at a specific activity of 46 Ci/mmole is described. The alkyne 4, efficiently prepared in two steps from readily available starting materials, was partially reduced to 9,11‐di‐__cis__‐retinoic acid 3 with both deuteri
High specific activity steroids I: 17α-ethynylestradiol-[9,11-3H] and norethindrone-[9,11-3H]
✍ Scribed by Howard Parnes; Emma J. Shelton
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- French
- Weight
- 379 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0022-2135
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
We report herein the first high specific activity tritium labelled synthesis of the widely used oral antifertility agents ethynylestradiol (5) and norethindrone (9). These substances were prepared at a specific activity of 54 Ci/mmol, a figure which is 48 and 377 times greater than any previously described preparations of (5) and (9) respectively. Microscale conditions were developed for all the steps in the sequence, including the Birch reduction (1), so that the initially high level of enrichment usually achieved in the reduction of Δ^9(11)^‐estradiol 3‐methyl ether was retained in the final products.
📜 SIMILAR VOLUMES
## Abstract Lithium borotritide reduction of α‐ionylidene‐acetaldehyde (5) followed by manganese dioxide oxidation provided the tritiated aldehyde (9) which retainad over 95% of the label. On treatment with the ylide derived from ethyl 4‐chloro‐3‐methylcrotonate, ethyl α‐retinoate‐11‐^3^H (14) was
## Abstract An improved synthesis of the tritium labelled form of the new pharmacon DIENOGEST is described. The [^14^α,15α‐^3^‐H]DIENOGEST was obtained with a specific activity of 51 Ci/mmol and a radiochemical purity > 98%.
## Abstract The synthesis of a [9α, 11α‐]‐tritium‐labelled new steroid with interceptive — post‐coital antifertility — activity, 3‐methoxy‐14β, 15β‐methylene‐estra‐1,3,5(10)‐triene‐17β‐ol, starting with the catalytic tritiation of 3‐methoxy‐estra‐1,3,5(10), 9(11)‐tetraene‐14α, 17β‐diol, is describe