Pyrido[2,3-d]pyrimidines and pyrido[2,3-d; 5-d′]dipyrimidines as potential chemotherapeutic agents. VIII

Reactions of 5-dimethylaminomethylene-6-imino-1,3-dimethyluracil hydrochloride (1) with active methylene compounds 2 and 4 yielded bi- and tricyclic heterocyclic compounds 3 and 5 . All the prepared compounds were screened for chemotherapeutical activities but none were active.     

Photoelectric effects in chlorophyll membranes

Photoinduced potentials and currents and photo-electroosmotic velocities were measured across cellulose acetate membranes impregnated with chlorophyll pigments. Chlorophyll was extracted by both solvent extraction, Chl^s, and column chromatography, Chl. Photoelectric effects in membranes prepared with the following pigments were investigated: (i) Chl^s-a + β-carotene, (ii) Chl^s-b + xanthophyll, (iii) Chl^s-a, (iv) Chl^s-b, (v) β-carotene, (vi) xanthophyll, (vii) Chl^s-a + anthraquinone, (viii) Chl^s-b + anthraquinone, (ix) Chl-a, (x) Chl-b, (xi) Chl-a + anthraquinone, (xii) Chl-b + anthraquinone, (xiii) Chl-a + benzoquinone, and (xiv) Chl-b + benzoquinone. β-Carotene, xanthophyll, Chl-a and Chl-b obrained by chromatographic separation do not show a photoinduced potential or current. However, these effects are observed when “pure” (doubly chromatographed) Chl-a or Chl-b are mixed with anthraquinone or benzoquinone. These effects are observed in systems (i), (ii), (iii), (iv), (vii) and (viii) involving Ch^s. Although photoinduced potentials and photoinduced currents are not observed in Chl-a or Chl-b membranes, photoelectroosmosis is still observed. p]Both photoinduced potentials and currents are found to depend on pH. When the pH is changed appropriately, Chl^s-a acts as photocathode while Chl^s-b becomes a photoanode. Photocurrents are considerably enhanced when the pH is lowered. The change of photopotential with temperature is found to be insignificant. Photoelectroosmosis is always found to be directed towards the dark side, regardless of the polarity of the electrodes. A model based on the role of plastiquinone has been proposed to explain these phenomena, which have excellent reproducibility. The model predicts that ΔpH = (pH)_d — (PH)₁ (where (pH)_d and (pH)₁ denote the pH on the dark and illuminated side of the membrane respectively) would be positive when the pH of the bathing solution is higher than approximately 7, while it would be negative for lower pH. This behaviour is observed in the case of mixture of pure Chl-a + anthraquinone and pure Chl-b + benzoquinone. The model also predicts photoelectroosmosis irrespective of the presence of plastiquinone, in agreement with experimental observation.     

Primordial cosmological inflation versus local supersymmetry breaking in SUSY GUTs coupled toN=1 supergravity

We present a model for a SUSY GUT coupled toN=1 supergravity in which local supersymmetry breaks down in the gauge singlet sector. The constraints for the model to be physically acceptable are incompatible with inflation. The simultaneous breaking of local supersymmetry and gauge symmetry is proposed as a good prospect for inflation.     

Colchiceine as an extractive indicator in the determination of copper(II)

Colchiceine, a new extractive indicator, is satisfactorily used in the determination of copper(II). A highly sensitive greenish yellow complex is formed with copper, which is extractable into chloroform. The results are comparable in sensitivity and selectivity with those of its precursors.     

Absolute stereochemistry of the insect antifeedant cadinene from eupatorium adenophorum

Chemical correlation studies and application of Horeau's method establish the absolute stereochemistry of the major cadinene from $\text{E}$. $\text{adenophorum}$ as shown in {=1}.     

Evaluation of thesscf andpy approximations for quadrupolar fluids

Two approximations, the single super chainf-expansion (sscf), and Percus-Yevick (py) approximation, are evaluated for a molecular fluid in which the molecules interact with a pair potential, that is the sum of Lennard-Jones and quadrupole-quadrupole parts at two values of reduced quadrupole moment. These results are compared with Monte-Carlo results. Except for the harmonic coefficienth (222;r), thesscf approximation seems to be quite accurate for the lower value of quadrupole moment but at higher valuespy approximation produces much better results except forh(220;r).