Synthesis Based On Cyclohexadienes .6. A New Total Synthesis Of (+/-)-Methyl Acorate And (+/-)-Methyl Epi-Acorate

A new method of construction of carbon-carbon bond is described. Thus the dianions generated from the metal-ammonia reduction of substituted benzoic acids readily undergo Michael addition with methyl crotonate resulting in synthetically useful products having a quaternary carbon. Based on this strategy, new syntheses of (+/-)-methyl acorate (14b) and (+/-)-methyl epi-corate (15) are reported.

Synthetic investigations on illudinine: a new synthesis of methyl 8-methoxy-2,2-dimethyl-7-oxo-1,2,3,5,6,7-hexahydro-s-indacene-4-carboxylate

A new strategy for the total synthesis of methyl 8-methoxy-2,2-dimethyl-7-oxo-1,2,3,5,6,7-hexahydro-s-indacene-4-carboxylate 4, a key intermediate in the synthesis of illudalanes, is reported. The key step in this strategy is a new method of preparation of indanones from tetralones. Thus, the furfurylidene derivative of 6-methoxy-3,4-dihydronaphthalen-1-(2H)-one is oxidised to the dicarboxylic acid 9a which is cyclodehydrated to methyl 7-methoxy-1-oxoindan-4-carboxylate 10. Similar reactions on the tetrahydronaphthalenone 25, obtained from 6-methoxy-1,2,3,4-tetrahydronaphthalene-7-carbaldehyde 11 by sequential transformations including a regiospecific benzylic oxidation resulted in the hexahydro-s-indacenone 4, thus completing a formal synthesis of illudinine 1.

Seasonal fluctuations in blue-green algae, especially in heterocystous species in polluted coastal waters off Helsinki city, in the northern part of the Gulf of Finland

Tiivistelmä

Vapor-liquid equilibriums: systems methyl ethyl ketone-p-xylene and chlorobenzene-p-xylene

Vapor-liquid equilibrium data have been measured for the binary systems methyl ethyl ketone-p-xylene and chlorobenzene-p-xylene, at 685 mmHg pressure. The activity coefficients have been evaluated taking Into consideration the vapor-phase nonideallty. The f-x-y data have been subjected to a thermodynamic consistency test and the activity coefficients have been correlated by the Wilson equation.

Dilute solution properties of methyl methacrylate—acrylonitrile copolymer (MA2)

This article deals with studies of the dilute solution properties of methyl methacrylate-acrylonitrile (MMA-AN) copolymer of 0.415 mole fraction (mf) of acrylonitrile composition. Mark—Houwink parameters for this copolymer have been evaluated in acetonitrile (MeCN), 2-butanone (MEK), dimethyl formamide (DMF), and γ-butyrolactone (γ-BL). The Mark-Houwink exponent a in all four solvents at all temperatures is larger than the corresponding values of the parent homopolymers. The solvent power is in the order of DMF < γ–BL < MEK < MeCN; [η] decreases with an increase in temperature, which is behavior characteristic of polymers in good solvent. The unperturbed dimensions (K0) values, obtained by the Stockmayer–Fixman method, are lower than those for the parent homopolymers and depend on solvent as well as temperature. The solute—solvent interaction parameter X1 values are close to 0.5; X1 is independent of temperature. The excess interaction parameter XABvalues are negative. The results for this copolymer system in regard to low second virial coefficient A2, large X1, and high a values suggest that the large extension of these copolymer chains is due to the unusual short-range interactions.

A Heat and Light Mediated Synthetic Sequence Serendipitous Synthesis of Methyl Ester of Tris-Norpterosin-E

Synthesis of methyl ester of 3-oxo-indan-5-acetic acid (3), an analogue of the natura1 product pterosin-E (4), starting from cyclopentadiene (1) and p-benzoquinone (2) using a sequence of six ground and excited state reactions, is described.