Photochemical three-membered rings synthesis

Suitable monomers are summarized in Table 9.1. 1,2,4-Triazole is a white to pale yellow solid with a melting point of 120°C. Synonyms are pyrrodiazole, IH-1,2,4-triazole, and 5-triazole. This compound should not be confused with a sulfanilamide compound that is addressed as triazole. In contrast to a triazole, a triazin refers to a 6-membered ring with three nitrogen atoms. 1,2,4-Triazole is used for the synthesis of agrochemicals, pharmaceutical substances, hydraulic fluids, and photochemical products. Both 1,2,4-triazole and 1,2,4-triazole are effective solvents for proton conducting electrol54es." ... 

Both materials were isolated in approximately 30 % yield. The iodo compound VII/175 was then reduced photochemically with tributyltinhydride to give 15-pentadecanolide [114]. Experiments with different cycloalkanones (five- to eight-membered) and different lengths of the side chain (two and three methylene groups) showed that this reaction can be used for the synthesis of several medium sized lactones [75] [80] [114]. Under similar reaction conditions, lactols can also undergo ring expansion reaction [115]. The substrates (steroidal lac-... 

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