Prostanoic acid

The prostaglandins (qv) constitute another class of fatty acids with aUcycHc structures. These are of great biological importance and are formed by i vivo oxidation of 20-carbon polyunsaturated fatty acids, particularly arachidonic acid [27400-91-5]. Several prostaglandins, eg, PGE [745-65-3] have different degrees of unsaturation and oxidation when compared to the parent compound, prostanoic acid [25151 -18-9]. 

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... 

Lubiprostone is a prostanoic acid derivative labeled for use in chronic constipation and irritable bowel syndrome (IBS) with predominant constipation. It acts by stimulating... 

As discussed previously, lubiprostone is a prostanoic acid derivative that stimulates the type 2 chloride channel (CIC-2) in the small intestine and is used in the treatment of chronic constipation. Lubiprostone recently was approved for the treatment of women with IBS with predominant constipation. Its efficacy for men with IBS is unproven. 

Chloride channel activator Lubiprostone, prostanoic acid derivative, stimulates chloride secretion into intestine, increasing fluid content... 

Some of the most recent and exciting developments in the field of natural products are related to the compounds known as prostaglandins. All are oxygenated unsaturated derivatives of prostanoic acid, which is a C20 fatty acid in which there is a cyclopentane ring formed by connecting the C8 and Cl2 positions ... 

The prostaglandins are a group of naturally occurring compounds whose molecular structures are based on that of prostanoic acid. 

Prostaglandins are naturally occurring carboxylic acids that are related to the fatty acids. They contain the carbon skeleton of prostanoic acid, with various additional unsaturations and oxygen groups. One example is provided by PGE2 ... 

PGs are named from a hypothetical compound, prostanoic acid, a monocarboxylic acid with 20 carbon atoms, arranged with two side chains with 7 and 8 carbon atoms linked to a cyclopentane ring. PGs have functional groups with oxygen at carbons 9, 11, and 15 of prostanoic acid (see Figure 16.23) and one, two, or three double bonds in the side chain. 

Figure 16.23 Structure of prostanoic acid and the cyclopentane ring of prostaglandins A through I a and indicate the orientation of the 9-hydroxy group.

The standard nomenclature for this family of readily released fatty acids from tissues and organs and the synthetic prostaglandin-like compounds is derived from the C-20 cyclopentane acid skeleton of the hypothetical prostanoic acid 1. 

Benzydamine, Imidazole congeners, 9, ll-azo-13 oxa-15 hydroxy prostanoic acid, 9, ll-azoprosta-5-13 dienoic acid (U-51605), 9, ll(epoxmethano) prostanoic acid, l(isopropyl-2-indloy (l)-3 pyridyl-3-ketone (L-8027). 

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. ... 

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