pletely eliminated in some cases, since much longer chains can now be sequenced than formerly. 2. Because of the good yields in the sequenator and the increased detection sensitivity for amino acids, the quantity of material required for sequence analysis will be considerably reduced. 3. The time required for the actual sequence analysis has already been greatly reduced, and 15 degradation steps can now be carried out in 24 hours. (The determination of the sequence of insulin by the DNP method took Sanger and three coworkers ten years, while Braunitzer and five colleagues, using a greatly improved method, spent six years on the sequencing of hemoglobin. The determination of the sequence of a chain of 150 amino acids by the classical manual Edman method takes two people about two years.)
In view of the growing importance of photochemically initiated reactions in industry, the use of free-radical additions of thiols to unsaturated compounds also seems promising. The present article is intended to demonstrate the possibilities and limitations of reactions of this type in organic synthesis.
Ozonolyses of 0-methyl oximes of acyclic ketones (7, 10, 19) and of cyclic ketones (16, 24, 27, 31) in the presence of acyclic ketones (8, 9, 17) or of cyclic ketones (18, 25, 26, 31) gave the corresponding tetrasubstituted cross-ozonides (13, 21, 29, 32). Ozonolyses of 0-methylated monooximes of 1,4-, 1 , 5 , and 1,6-dicarbonyl compounds (35b-f) gave the corresponding bicyclic ozonides 36b-f.
Die zunehmende Bedeutung photochemisch initiierrer Reaktionen in der Technik 16Jt auch die Nutzung radikalischer Additionen von Thiolen an ungescittigte Verbindungen aussichtsreich erscheinen. Dieser Aufsatz sol1 Miiglichkeiten und Crenzen der An wendung derartiger Reaktionen in der organischen Synthese aufzeigen.
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