Carba

Acetate Benzoate p-Nltro benzoate 3 5-Dl-nltro benzoate Aryloxy- acetlc Acid JVJV-Dl- phenyl- carba- mate iv-a- naphthyl- carba- mate p-Tolu- enesul- phonate 2 4- Dlnltro- phenyl Ether... 

W. C. Sumptei and F. M. MiUei, Eleterocpclic Compounds with Indoland Carba le Systems, Inteiscience PubHsheis, New Yoik, 1954, p. 173. 

Second-row elements, particularly phosphorus and sulfur, stabilize adjacent carba-nions. The pATs of some pertinent compounds are given in Table 7.10. 

A mixture of 125 g of o-(pethyl chlorocarbonate in 150 ml of ether. The mixture is kept at room temperature for 3 days, diluted with about 500 ml of water and extracted with 300 ml of ether. The ethereal extract Is washed with 300 ml of water, dried over calcium chloride, filtered and concentrated. The resulting ethyl o-(pnext step without further purification. 

In 10 ml of ethanol was dissolved with heating 200 mg of 2-methyl-6-(1-methoxy-2-carba-moyloxyethyl)-1,4-benzoquinone and the resulting solution was cooled. To the cooled solution was added 0.5 ml of aziridine and then the resulting mixture was allowed to stand In a refrigerator at 5°C to 8°C for 4 days. Thereafter, the crystalline substance which precipitated in situ was recovered by filtration and washed with ethanol to give 50 mg of the desired product as red crystals melting at 200°C (with decomposition). 

Benzhydryl 3-carbamoyloxymethyl-7j3-(2-thienylacetamido)-70 -methoxydecephalosporanate (300 mg) in 0.5 ml in anisole and 2.5 ml of trifluoroacetic acid is reacted for 15 minutes at 10°C. The resulting mixture is evaporated at reduced pressure and flushed twice with anisole. The residue is dissolved in methylene chloride and extracted with 5% sodium bicarbonate solution. The aqueous solution is adjusted to pH 1. B with 5% phosphoric acid and extracted with ethyl acetate. The organic solution is dried and evaporated to yield the pure 3-carba-moyloxymethyl-70 -methoxy-7/3-(2-thienylacetamido)decephalosporanic acid, MP 165°C to 167°C. This may then be converted to the sodium salt. 

The compound, which consists of the 17-phosphate of estradiol-3-N-bis((3-chloroethyl)carba-mate, melts under decomposition at about 155°C. It is soluble in an aqueous solution of alkali. 

With regard to the resolution of enantiomers, some applications can be found with modified silica gel supports. Thus, a Pirkle-type CSP was used for the separation of 200 mg of a racemic benzodiazepinone [75]. Also tris-(3,5-dimethylphenyl)carba-mate of cellulose coated on silica [91, 92] was applied successfully to the resolution of the enantiomers of 2-phenoxypropionic acid and to oxprenolol, alprenolol, propranolol among other basic drugs. However, the low efficiency of this technique and the relative high price of the CSPs limits its use to the resolution of milligram range of sample. 

NYL CHLORIDE AND 2 AZETIDINONE 4 4-dimethyl, 46,51 2- Azetidmones, preparation of, 46,56 o Azidobiphenyls, decomposition to m-trenes and cyclization to carba-zoles, 46, 88... 

Muscarinic agonists and antagonists are used for the treatment of a variety of pathophysiological conditions. For example, muscarinic agonists (pilocarpine, carba-chol, or aceclidine) reduce intraocular pressure when... 

The (non-detachable) prefix carba- signifies replacement of a heteroatom by carbon in general natural product nomenclature [26], and may be applied to replacement of the hemiacetal ring oxygen in carbohydrates if there is a desire to stress homomorphic relationships. If the original heteroatom is unnumbered, the new carbon atom is assigned the locant of the non-anomeric adjacent skeletal atom, with suffix a . 

Deoxy-4a-carba-p-D-eryfhro-pentofuranosyl)thymine or 4 a-carbathymidine... 

Structures in which the linking glycosidic oxygen is replaced by -CH2- may be named by use of the replacement prefix carba- (c/. 2-Carb-34.2) for emphasis of homomorphic relationships. The oxygen replaced is given the locant of the carbon atom to which it is attached in the residue with the lower roman numeral (cited as superscript) (cf 2-Carb-37.2), with suffix a1. 

Scheme 9.33 Synthetic strategy toward carba-sugars, Amaryllidaceae alkaloids, and undecenolides.

CHEMISTRY OF CARBA-SUGARS (PSEUDO-SUGARS) AND THEIR DERIVATIVES... 

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