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Carbonised textiles were found in a burnt down building inside a cave 30km from the far eastern coast of Russia. The textiles were made from untwisted or hand-twisted blades of sedge grass to form ropes, nets and woven mats. Dated by AMS to c. 9400–8400 cal BP these are the earliest textiles so far known from East Asia.

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Die Nitrierung der Titelverbindungen( I) wird untersucht.

Products of the steady-state photolysis of 2,2,4,6-tetramethyl-1,2-dihydroquinoline (1) in water, methanol, and water--ethanol were isolated for the first time and identified by IH and J3C NMR spectroscopy, IR spectroscopy, and mass spectrometry. As a result of the photolysis, the molecule of the solvent is added to the double bond of the heterocycle with formation of 4-hydroxy-(2) or 4-methoxy-2,2,4,6-tetramethyl-1,2,3,4-tetrahydroquinoline (3) in water and methanol, respectively. Compounds 2 and 3 are converted gradually into 1 in the dark. The rate of the back reaction depends on the solvent and the concentration of the product.Comparison of the products of the photolysis in methanol and hexane at 45 ~ and of the azoisobutyronitrile-initiated oxidation of 1 at the same temperature has shown that unlike the photolysis in hexane, aminyl radicals are not precursors of the product of the photolysis in methanol. The reaction proceeds via an excited singlet state.Key words: t,2-dihydroquinolines, photoaddition to the double bond, steady-state photolysis, effect of a solvent, lH and 13C NMR.Effect of the medium on the mechanism and kinetics of chemical transformations is one of the key problems of modern physical chemistry. The polarity of medium and hydrogen bonding between a reagent and a solvent play the most important role in this phenomenon. We have found earlier that the nature of the solvent affects the direction and the kinetics of photolysis of 2,2,4,6-tetramethyl-1,2-dihydroquinoline (1). t 6-Substituted and partly hydrogenated quinolines of general formula A, especially ethoxyquin (R I = EtO and R 2 = H), are widely used as antioxidants and antiozonants for rubbers, 2 as stabilizers for vitamin A and 13-carotene in feed, and as a post-harvest dip for apples. 3,4 Upon photolysis of these compounds in organic solvents (alkanes, benzene, toluene, and propan-2-ol), the hydrogen atom is split out from the molecule of dihydroquinoline and an aminyl radical is formed, which decaysat the ambient temperature predominantly in recombination reaction s giving a l-8"-dimer B. 6,7 The rate constants of the recombination of the transient radicals measured by flash-photolysis s and by ESR 7 are close and vary from 106 to 107 L tool -1 s -l depending on the substituent in position 6 and the solvent character. If the parent 1,2-dihydroquinoline has a substituent R 2 ~ H in position 8, the rate constant for radical decay dramatically decreases and becomes equal to 102 L tool -I s-I. 7The photolysis of aqueous solutions of compound I (A with R 1 = Me and R 2 = H) gives a product the absorption spectrum of which significantly differs from that of the dimer. 1 The kinetics of the decay of the transient species changes crucially: it follows the firstorder law with the rate constant depending on pH and varying from 25 s -t in acidic and neutral solutions to 3.9 s -~ in alkaline solutions i at the pH range corresponding to the value of pK a 10.4 measured for the transient species. ~ These experiments pose a number of questions con...