A systematic preparation of new contracted Gaussian-type orbital sets. VIII. MINI-1 and MIDI-1 sets for Ga through Cd

Minimal contracted Gaussian basis sets are presented for Ga through Cd. Characteristically these Gaussian-based minimal sets give far better d orbital energies than those by minimal STO basis sets. These new basis sets were tested on Br₂ for which a new benchmark calculation was also performed. The test result is satisfactory in that these basis sets produce good general agreement with the near Hartree–Fock calculation with respect to the molecular spectroscopic constants.     

Penicillin-cephalosporin conversion X. New synthesis of dithioazetidinones from thiazoline-azetidinones

New ring-opening reaction of thiazoline-azetidinones 1 to dithioazetidinones 2 was achieved with 2-benzothiazolyl disulfide in aqueous acidic media and its potentiality for the preparation of a variety of cephalosporins 3 from various thiazoline-azetidinones 1 is demonstrated.     

A facile access to α-phenylselenenyl carbonyl compounds by electrochemical oxidation

A novel α-phenylselenenylation of carbonyl compounds has been performed by electrolysis of a solution of ketones, diphenyl diselenide, tetraethylammonium bromide, and magnesium bromide in polar solvents (MeOH, AcOH, MeCN). The electrolysis enables us to prepare the desired seleno-carbonyl compounds without employing strong bases and the activated selenenyl reagents PhSeX.     

Approximate relativistic correction term

It is demonstrated that the first-order relativistic correction term to the Schrödinger hamiltonian for the hydrogen-like atom,

cannot be used safely even for small values of atomic number, Z, in the variational calculation. A modified form of the operator R is proposed so that one may incorporate it into the variational treatment of molecular systems.     

A novel selenium-mediated spiroannelation : one-step preparation of d1-theaspirane fron α-dihydroionol

d1-Theaspirane (1) was prepared by the selenium-mediated electrochemical oxidation of α-dihydroionol (3), via a novel selenium-mediated spiroannelation.     

Pd(O)-catalyzed electroreductive cleavage of allylic acetates

Pd(O)-catalyzed electroreductive cleavage of allylic acetates yielding alkenes and/or allyltrimethylsilanes is described. Deprotection of allyl esters can be performed in the same electrolysis system.     

University timetabling by constraint-based reasoning: A case study

This paper presents a case-study which applies constraint-based reasoning to university timetable planning. The timetabling problem is formulated as a constraint satisfaction model and this model is solved using constrained-directed search algorithms with built-in forward checking and constraint propagation. The model and algorithms were tested with real data containing 536 lessons to be scheduled into 45 timeslots and 21 rooms. The solution to the problem was obtained with minimal computing effort and processing time. This study showed that modelling and remodelling could be carried out easily through a proposed parameterised model formulation. The proposed approach has also successfully maximised room utilisation and minimised the number of timeslots required to deliver all the lectures. This finding may facilitate the widespread implementation of automated timetabling systems to larger scale problems and a wider variety of application domains.     

Penicillin-cephalosporin conversion-XI. Synthesis of 7-(α-substituted phenylacetoamide) cephalosporins by utilization of all the framework elements of penicillin G

A successful synthesis of clinically significant cephalosporins 2a-c with use of all the framework elements of penicillin G is described.     

A facile cleavage of oxirane with hydrazoic acid in dmf A new route to chiral β-hydroxy-α-amino acids

Chiral β-hydroxy-α-amino acids such as erythro-β-hydroxy-L-aspartic acid and erythro-β-hydroxymethyl-L-serine derivatives have been synthesized in optically pure form from L- and D-tartaric acids through a novel oxirane ring-opening reaction and a selective reduction of α-hydroxy ester as key steps.     

A halide ion promoted electrochemical oxyselenenylation of olefins

A novel electrolytic transformation of olefins $\text{1}$ into oxyselenides $\text{2}$ has been performed in high yields and high regioselectivities by elctrolyzing olefins in protic solvents (MeOH, AcOH, H₂O-MeCN) containing Et₄NX (X = Cl, Br, I) and diphenyl diselenide using platinum foils.