Prostanoic acid, synthesis

Compound 78, or prostanoic acid, the simplest prostaglandin compound, contains an a-side chain and also an co-side chain. Asymmetric synthesis of prostaglandins must involve the assembly of these subunits, as well as the introduction of other functionalities. 

An important example of heterogeneous diastereoselective synthesis by catalytic way is the synthesis of prostaglandines (a family of compounds having the 20-carbon skeleton of the prostanoic acid) (Scheme 14.14). Naturally, these molecules are biosynthesized via a cyclooxygenase enzyme system that is widely distributed in mammalian tissues. Many of the synthetic routes [272] involve the diastereoselective hydrogenation of a carbonylic bond having a C=C double bond... 

Since the 1,4-y-adducts can be converted to various types of bicyclic compounds, 1,4-addition of allyiic sulfoxides to enones provides a useful tool for stereoselective synthesis of cyclic compounds. Further, the 1,4-addition can be utilized in a three-component coupling process for synthesis of prostanoic acid derivatives (Scheme 20). Typical examples of addition of the Uthio derivative (78) of ( )-allyl p-tolyl sulfoxide to cyclic enones are summarized in Scheme 21. ... 

The answer is d. (Murray, pp 258-297. Scriver, pp 2705-2716. Sack, pp 121-138. Wilson, pp 362-367.) Infants placed on chronic low-fat formula diets olten develop skin problems, impaired lipid transport, and eventually poor growth. This can be overcome by including linoleic acid to make up 1 to 2% ol the total caloric requirement. Essential fatty acids are required because humans have only A", A , A , and A fatty acid desaturase. Only plants have desaturase greater than A . Consequently, certain fatty acids such as arachidonic acid cannot be made from scratch (de novo) in humans and other mammals. However, linoleic acid, which plants make, can be converted to arachidonic. acid. Arachidonate and eicosapentaenoate are 20-carbon prostanoic acids that are the starting point of the synthesis of prostaglandins, thromboxanes, and leukotrienes. 

The report will be divided into two sections (a) Syntheses of natural prostaglandins and (b) Syntheses of unnatural prostanoic acids and related analogs. Since PGEs can be transformed to PGFs and PGAs, any synthesis of PGE also constitutes, in principal, a synthesis of the corresponding PGF and PGA. ... 

Fried and coworkers reported the synthesis of some 7-oxa analogs of prostanoic acid and their cyclohexane analogs. Some of these compounds were found to be prostaglandin antagonists. Compounds and 49. have also been shownto produce smooth muscle responses. 

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