Klein’s compound

The crystalline stractirre of Klein s compound consists of a three-dimensional fiamewoik of AIO4 tetrahedra sharing comers, with Ca and S04 ions located in the existing cavities. It belongs to the tetragonal system (Zhang et ai, 1992). Above about 1350°C this phase becomes irrtstable and starts to decompose (Puertas et ai, 1995). 

Ca5(P04)30H. Main reaction product in the hardening of calcium phosphate cements. kleinite=Klein s compound... 

Ohle s formula essentially expressed the same features as are embodied in the orthoester formulas proposed six years later for this type of sugar derivative. Unlike Helferich and Klein s glucose tetraacetate, this new benzoyl-derivative may very well possess an orthoacid structure, since the slightest alkalinity of the medium causes a rapid rearrangement of the compound into the normal 6-derivative. - On the other hand, the new glucose tetraacetate of Helferich and Klein probably possesses a normal structure, since it is comparatively stable in alkaline medium, in fact, it is obtained from the 1,2,3,4-tetraacetate by the action of dilute alkali. 

Ursula Klein, Origin of the Concept of Chemical Compound, Science in Context 7 (1994) 163-204, and her E.F. Geoffroy s Table of Different Rapports Observed between Different Chemical Substances—a Reinterpretation, Ambix 42 (1995) 79-100. See also J.B. Gough, Lavoisier and the Fulfillment of the Stahlian Revolution, Osiris 4 (1988) I5-33-... 

Klein, Origin of the Concept of Chemical Compound, and her Geoffroy s Table. Her accounts provide detailed illustrations of my general story of the move from metaphysical to experiential composition. 

Rossman, TG, Molina, M., Meyer, L., Boone, P, Klein, C.B., Wang, Z., Li, F., Lin, W.C. Kinney, PL. (1991) Performance of 133 compounds in the lambda prophage induction endpoint of the Microscreen assay and a comparison with S. typhimurium mutagenicity and rodent carcinogenicity assays. Mutat. Res., 260, 349-367... 

Minerals and other compounds Ideal formula (Klein, 2002) Typical arsenic concentration (mg kg"1) Reference(s)... 

RD Klein, TG Geary. Method of identifying compounds useful as antiparasitic drugs. U.S. Patent 5,079,143, 1992. 

L. Pauling and Z. S. Herman, The unsynchronized-resonating-covalent-bond theory of metals, alloys, and intermetallic compounds, in Valence Bond Theory and Chemical Structure, D. J. Klein and N. Trinastic, eds., Elsevier, Amsterdam, 1990, pp. 569-610. 

Klein et al. (978) first attempted the alkaline hydrolysis of 3-chloropyrazine 1 -oxide to 3-hydroxypyrazine 1 -oxide, and although spectroscopic evidence indicated the formation of the hydroxy compound, good quality homogeneous material could not be isolated. Later work by Berkowitz and Bardos (1034) has shown that 3-chloropyrazine 1-oxide was hydrolyzed by refluxing with two equivalents of aqueous sodium hydroxide, and treatment of the product with trimethylsilyl chloride and triethylamine gave 3-(trimethylsilyl)oxypyrazine 1-oxide. 3,6-Di-s-butyl-2-hydroxypyrazine 1-oxide has been prepared from the chloro analogue (no details given) (982). Hydrolysis of 2-amino-6-chloro-3-cyano-5-methylpyrazine... 

Klein and Kdnig," for example, have reported the synthesis of a sulfonamide substituted 1,2-aryldiyne 111, where the sulfonamide group, being a cr-acceptor, should facilitate the Bergman cycloaromatization. However, as reported by Zaleski for a series of l,S-bis substituted oct-4-ene-2,6-diyne derivatives 113, steric hindrance and hydrogen bond formation between the terminal substituents can influence the temperature of the cyclization, and therefore the reactivity of the sulfonamide compound 111 is comparable with the one of the unsubstituted analog 112, since the electron withdrawing effect of the substituent is compensated by its steric hindrance (Scheme 19.30). 

T. Christensen, A. Werner and G. Richter, A. Werner and J. L. Klein, and P. Pfeiffer and M. Tilgner. The compounds include (1) the acid and its monohydrate or dihyrate (2) sodium (3) potassium—Reinecke s salt—and (4) its complex with potassium iodide ... 

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