Synthetic GnRH agonists

Synthetic GnRH Agonists Synthetic derivatives of GnRH with more biological activity than the native hormone have been used for the suppression of spermatogenesis after 2 or more weeks of treatment that downregu-lated GnRH receptors in the anterior pituitary. However, in most trials there was no uniform induction of azoospermia, probably because the reduction of LH and testosterone secretion was incomplete. 

The same method was applied to the synthesis of [ CJcarboxylic acid 22 from the more complex substrate o-chloroaryl iodide 32 to provide the product in 87% chemical yield and 32% overall radiochemical yield from barium [ CJcarbonate . The acid 33 was a key intermediate in the preparation of a series of labeled GnRH receptor agonists of the amide type. The tolerability of this methodology towards COOR, CHO, CN, NO2, OR, NH2, NR2, Cl, CF3, COR demonstrates that in cases like the above procedure it can be superior to classical [ CJcyanations or [ CJcarboxylations. For multifunctional substrates such as 32. it enables the introduction of carbon-14 at a later synthetic stage than would otherwise be possible. 

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