Calcium ammonia

The lithium (or calcium) ammonia system apparently does not have severe conformational requirements, since a 17 -acetoxy-20-ketone reacts to give the... 

Doumaux, A.R., Jr., Marked differences between the sodium-ammonia and calcium-ammonia reduction of nitriles, J. Org. Chem., 37, 508-510, 1972. 

The oil content of liquid ammonia can be tested gravimetrically by first evaporating the ammonia liquid and then concentrating the ether extract of the residue. Iron, aluminum, calcium (ammonia catalyst) and other impurities can then be determined in the ether-insoluble residue. 

In the synthesis of the antidepressant (-)-Rolipram, Meyers et al. [26] tried to convert bicyclic lactam 39 to hydroxylactam 40 by use of dissolved metals. The increased yield of 40 on going from Li -> K -> Na parallels fhe reduction potential of the metals Li (3.0), K (2.9), and Na (2.7). The reduction potential of calcium is known to be even lower. When 39 is treated with calcium metal (10 equiv.) in liquid ammonia, fhe desired 40 is produced in 84% yield (Scheme 4.11). The same type of reduction is applicable to the conversion of 41 to 42 [27]. Furthermore, treatment of tricyclic lactam 43 wifh EtsSiH and I ifTi gives poor isolated yield (22%) of the polar diamino alcohol 44. In contrast, calcium-ammonia reduction of 43 produces N-unsubstituted hydroxylactam 45 in an excellent yield. 

Metallic bronze fh(N 11, ), can, furthermore, be prepared from calcium-ammonia solution by evaporation of the ammonia. A bronze sohd is obtained, which in TH F at -30 °C behaves as a sohd surface in its reaction with alkyl hahdes (Scheme 4.17) [39]. Its apphcation in the reduction of 61 b produces a mixture of cyclopropane derivative 62 (81%) and straight-chain diphenylbutane 64 (8%). The process involves the formation of a tight anion radical-cation radical as an intermediate. Carbon-halogen bond cleavage occurs on the surface of the metalhc cluster. 

Calcium, ammonia, 95% yield. For this method to work the oxide coating on the Ca must be removed. This is sometimes accomplished by stirring with sand. 

The structure of isoeremophilone 66 was established by correlation with the compound derived from calcium/ammonia reduction of the acetate of 1,11-diene (58). Alloeremophilone (67), also reported as a minor constituent of E. mitchelli, can be generated from the acetate of HDE (57) by pyrolysis, which also yields equivalent amounts of eremophilone (59). 

B. Other useful laboratory studies include electrolytes, glucose, BUN, creatinine, calcium, ammonia, liver transaminases, bilirubin, prothrombin time (PT), amylase, serum osmolality and osmolar gap (see p 32 serum levels > 1500 mg/L may increase the osmolar gap by 10 mOsm/L or more), arterial blood gases or oximetry, and EGG monitoring. Valproic acid may cause a falsepositive urine ketone determination. 

Wasse JC, Howard CA, Thompson H et al (2004) The stmcture of calcium-ammonia solutions by neutron diffraction. J Chem Phys 121 996-1004... 

Compressibility and Viscosity. Maybury and Coulter have obtained the compressibilities of sodium-, lithium-, and calcium-ammonia solutions from sound-velocity measurements using the relation,... 

Amines. Calcium-ammonia reduction of cycloheptyl cyanide gives a reasonable yield of cycloheptylmethylamine. ... 

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