- New methodology for the synthesis of tetrahydrofuro[3,2-b]furan-2(3H)-one derivatives, synthons of natural products with biological interest
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A new methodology is presented to synthesize in a regio and stereoselective manner tetrahydrofuro[3,2-b]furan-2(3H)-one, structural subunit present in a wide variety of natural products present in plant, fungi, algae, insects, and other living organisms.
- Monta?a, ángel M.,Barcia, Joan A.,Grima, Pedro M.,Kociok-K?hn, Gabriele
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- FAR SUPERIOR OXIDATION CATALYSTS BASED ON MACROCYCLIC COMPOUNDS
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An especially robust compound and its derivative metal complexes that are approximately one hundred-fold superior in catalytic performance to the previously invented TAML analogs is provided having the formula (I) wherein Y1, Y2, Y3 and Y4 are oxidation resistant groups which are the same or different and which form 5- or 6-membered rings with a metal, M, when bound to D; at least one Y incorporates a group that is significantly more stable towards nucleophilic attack than the organic amides of TAML activators; D is a metal complexing donor atom, preferably N; each X is a position for addition of a labile Lewis acidic substituent such as (i) H, deuterium, (ii) Li, Na, K, alkali metals, (iii) alkaline earth metals, transition metals, rare earth metals, which may be bound to one or more than one D, (iv) or is unoccupied with the resulting negative charge being balanced by a nonbonded counteraction; at least one Y may contain a site that is labile to acid dissociation, providing a mechanism for shortening complex lifetime. The new complexes deliver catalytic performances that promise to revolutionize multiple oxidation technology spaces including water purification.
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Page/Page column 83
(2017/04/11)
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- Long-lived homogenous oxidation catalysts
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A robust chelate complex is provided having the formula: STR1 wherein M is a metal, preferably a transition metal; Z is an anionic donor atom, at least three of which are nitrogen and the other is preferably nitrogen or oxygen; L1 is a labile l
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- An unexpected formation of a new 3-imidazoline free radical
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A new 3-imidazoline has been formed unexpectedly in the reaction between 2,4-dibromo- 2,4-dimethylpentanone-3 and concentrated aqueous ammonia. A crystalline nitroxide formed upon oxidation with hydrogen peroxide. Its identity has been proved by X-ray analysis. A feasible mechanism for the present reaction is given.
- Rijk,Tesser
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p. 2129 - 2134
(2007/10/02)
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- Branched amides of L-aspartyl-D-amino acid dipeptides
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Amides of L-aspartyl-D-amino acid dipeptides of the formula STR1 and physiologically acceptable cationic and acid addition salts thereof wherein Ra is methyl, hydroxymethyl, ethyl, n-propyl or isopropyl; R is STR2 where at least one of R3, R4, R5, R6 is alkyl having from one to four carbon atoms and the remainder are hydrogen or alkyl having from one to four carbon atoms, and the sum of the carbon atoms in R3, R4, R5 and R6 is not greater than six; and when both of R3 and R4 or R5 and R6 are alkyl, they are methyl or ethyl. Said amides are potent sweeteners having advantages over the prior art, edible compositions containing them, methods for their use in edible compositions and novel amine and amide intermediates useful in their production.
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- NATURE OF THYOXYALLYL INTERMEDIATE IN THE DECOMPOSITION OF ALLENE EPISULFIDE AND PYRAZOLINE-4-THIONE
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Thermolysis of tetramethylallene episulfide (10) gave 2,4-dimethyl-3-mercaptopenta-1,3-diene(12) via thioxyallyl intermediate(13) by unimolecular C-S bond cleavage. 3,3,5,5-Tetramethylpyrazoline-4-thione(11) also gave 12 probably via the same intermediate(13), which has a biradical character.
- Furuhata, Toshiya,Ando, Wataru
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p. 5301 - 5308
(2007/10/02)
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- Branched amides of L-aspartyl-D-amino acid dipeptides
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Amides of L-aspartyl-D-amino acid dipeptides of the formula STR1 and physiologically acceptable cationic and acid addition salts thereof wherein Ra is CH2 OH or CH2 OCH3 ; R is a branched member selected from the group consisting of fenchyl, diisopropylcarbinyl, d-methyl-t-butylcarbinyl, d-ethyl-t-butylcarbinyl, di-t-butylcarbinyl, 2-methylthio-2,4-dimethylpentan-3-yl, STR2 where at least one of R3, R4, R5, R6 is alkyl having from one to four carbon atoms and the remainder are hydrogen or alkyl having from one to four carbon atoms, X is O, S, SO, SO2, C=O or CHOH; m is zero or 1-4, n and p are each zero, 1, 2 or 3 where the sum of n+p is not greater than 3 and the sum of the carbon atoms in R3, R4, R5 and R6 is not greater than six, and when both of R3 and R4 or R5 and R6 are alkyl they are methyl or ethyl, STR3 where one of R7, R8, R9 is alkyl having from one to four carbon atoms and the remainder are hydrogen or alkyl having from one to four carbon atoms and the sum of the carbon atoms in R7, R8 and R9 is not greater than six, m and q are the same or different and each have the values previously defined for m; STR4 where each of R12 and R13 are methyl or ethyl, or R12 is hydrogen and R13 is alkyl having from one to four carbon atoms, Z is O or NH and t is 1 or 2, STR5 where W is 1-4, R14 and R16 are each alkyl having from one to four carbon atoms, R15 is H, OH, methyl or ethyl and the sum of the carbon atoms in R14, R15 and R16 is not greater than six and when both of R14 and R15 are alkyl they are methyl or ethyl, and STR6 where R17 and R19 are alkyl having from one to four carbon atoms, R18 and R20 are H or alkyl having one to two carbon atoms, A is OH and B is H, OH or CH3 and taken together A and B are STR7 where the sum of the carbon atoms in R17, R18, R19 and R20 is not greater than six and when both of R17 and R18 or R19 and R20 are alkyl they are methyl or ethyl; said amides are potent sweeteners having advantages over the prior art, edible compositions containing them, methods for their use in edible compositions and novel amide intermediates useful in their production.
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