Darstellung,Kristallstrukturen und Schwingungsspektren von Verbindungen mit den linearen Dipnictidoborat(3–)‐Anionen [P–B–P]3–, [As–B–As]3– und [P–B–As]3–

Synthesis, Crystal Structure, and Vibrational Spectra of Compounds with the Linear Dipnictidoborate (3–) Anions [P–B–P]^3–, [As–B–As]^3–, and [P–B–As]^3– The alkali metal boron compounds M₃[BX₂] with X = P, As are synthesized from the alkali metals M and the binary components MX or M₄X₆ and BX in sealed steel ampoules (phosphides) or niobium ampoules (arsenides) at 1000 K. The compounds are obtained as bright yellow prisms (M₃[BP₂]) or plates (K₂Na[BP₂]) and yellow‐red prismatic crystals (M₃[BAs₂], Cs₃[BPAs]) which are very sensitive against oxidation and hydrolysis. Three different structure types are formed, namely K₂Na[BP₂] (C2/m (No. 12); Z = 4; a new mC24 structure type); Na₃[BP₂] (P2₁/c (No. 14); Z = 4, β‐Li₃[BN₂] type), M₃[BX₂] with M = K, Rb, Cs and X = P, As and Cs₃[P–B–As] (C2/c, (No. 15); Z = 4, K₃[BP₂] type). The bond lengths of the linear [BX₂]^3– anions are hardly changed and correspond to a Pauling bond order PBO = 1.9 (d(B–P) = 176.7–177.1 pm; d(B–As) = 186.5–188.0 pm). The vibrational spectra confirm the existence of unmixed and mixed units [P–B–P]^3–, [As–B–As]^3– and [P–B–As]^3– with D_∞h and C_∞v symmetry, respectively. The valence force constants f(B–X) and the corresponding Siebert bond orders, calculated from the frequencies, are discussed and compared with those of the isoelectronic anions and molecules.     

Dibrommethylsulfoniumsalze – Darstellung und Kristallstruktur [1]

Dibromomethylsulfoniumsalts — Preparation and Crystal Structure The salts CH₃SBrA^? (A^? = SbCl, AsF) were prepared by various routes and characterized by their Ramanspectra. CH₃SBrAsF crystallized in the monoclinic space group P2₁/c with a = 770,5(4) pm, b = 942,4(12) pm, c = 1329,3(14) pm, β = 100,28(6)°, Z = 4. Distances and bond angles in the cation are as expected.     

Carbon-13 NMR of polycyclic aromatic compounds. 1—Methoxybenz[a]anthracene-7, 12-diones

Benz[a]anthracene-7, 12-dione, eight monomethoxybenz[a]anthracene-7, 12-diones and two dimethoxybenz[a]anthracene-7, 12-diones were analyzed by ¹³C and ¹H NMR. All ¹³C and ¹H resonances have been assigned. Substituent effects on the ¹³C chemical shifts are discussed.     

Studies in spiroheterocycles. Part XIII. Synthesis of a novel spiro system: Spiro[9H-acridine-9,3′-[3h]indol]-2′(1′H)-one and related compounds from new fluorinated spiro[3H-indole-3,9′-[9H]xanthen]-2(1H)-ones

A new spiroheterocyclic system spiro[9H-acridine-9,3′-[3H]indol]-2′(1′H)-one and related compounds have been prepared by the reaction of spiro[3H-indole-3,9′-[9H]xanthen]-2(1H)-ones with aromatic amine or ammonium acetate. The latter were prepared by heating fluorinated indole-2,3-diones with m-/p-cresols or α-naphthol in the presence of sulphuric acid at 230-240°. The synthesized compounds have been characterized on the basis of their elemental analyses, ir, nmr (1_H, 13_C, 19_F) and mass spectral data.     

Condensation of o-aminophenol and α-dicarbonyl compounds. Part 1. Benzoxazines

By condensation with o-aminophenol of a series of phenylglyoxal derivatives two species of products were obtained, namely 2-hydroxy-(2H)-1,4-benzoxazines (I) and 2′ -aryl-2,2′ -dibenzoxa-zolines (II). The structure of compounds I was investigated by ir, uv and pmr spectroscopy and a reaction mechanism was proposed. J. Chem. Soc., 14, 997 (1977)     

Thermal [1, 3] benzoyl migration in 1-(α-benzoyloxyarylideneamino)-1,2,3-triazoles. Part II

1-(α-Benzoyloxyarylideneamino)-4, 5-dirnethyl-1,2,3-triazoles (V) were prepared by reacting the sodium salt of substituted 1-benzoylamino-4, 5-dimethyl-1,2,3-triazoles (IV) with benzoyl chloride at ?50°. The uncatalyzed thermal isomerization of isoimides V to the corresponding imides VI was studied kinetically and the reaction mechanism is discussed.     

Pterin Chemistry. Part 92.. Loading experiments with 6α,β-tetrahydro-L-[3′-2H1] biopterin

6α,β-Tetrahydro-L -[3′-²H₁]biopterin ([3′-²H₁]- 1 ) was administered orally to two primapterinuric patients in order to investigate the biosynthetic pathway of 7-substituted pterins in humans. L -Primapterin ( 2 ) and L -biopterin were isolated from urine after loading and measured by GC/MS. L -Biopterin and L -primapterin were labelled with ²H to an equal extent. From this result, one can conclude that L -primapterin is formed from tetrahydro-L -biopterin, very probably via an intramolecular rearrangement.     

Polycyclic nitrogen compounds. Part iii. Synthesis of 3,3a-dihydrothiazolo[3,4-α]quinoxalin-4-ones

New tricyclic quinoxalinone skeletons with bridge-head nitrogen atoms and containing sulphur in a fully-reduced five-membered ring C were obtained. 3,3a-Dihydrothiazolo[3,4-α]quinoxalin-4-ones I-III were prepared by metal-acid reductive cyclisation of N-(nitrophenyl)- and N-(dinitrophenyl)thiazolidine-4-carboxylic acids IVa,b,c. Attempts to obtain the skeleton by selective hydrogen transfer reductive cyclisation of the corresponding esters Va,b,c were unsuccessful.     

Schwache Sn…I‐Wechselwirkungen in den Kristallstrukturen der Iodostannate [SnI4]2– und [SnI3]–

Weak Sn…I Interactions in the Crystal Structures of the Iodostannates [SnI₄]^2– and [SnI₃]^– Iodostannate complexes can be crystallized from SnI₂ solutions in polar organic solvents by precipitation with large counterions. Thereby isolated anions as well as one, two or three‐dimensional polymeric anionic substructures are established, in which SnI₃^– and SnI₄^2– groups are linked by weak Sn…I interactions. Examples are the iodostannates [Me₃N–(CH₂)₂–NMe₃][SnI₄] ( 1 ), (Ph₄P)₂[Sn₂I₆] ( 2 ), [Me₃N–(CH₂)₂–NMe₃][Sn₂I₆] ( 3 ), [Fe(dmf)₆][SnI₃]₂ ( 4 ) and (Pr₄N)[SnI₃] ( 5 ), which have been characterized by single crystal X‐ray diffraction. [Me₃N–(CH₂)₂–NMe₃][SnI₄] ( 1 ): a = 671.6(2), b = 1373.3(4), c = 2046.6(9) pm, V = 1887.7(11) · 10⁶ pm³, space group Pbcm;(Ph₄P)₂[Sn₂I₆] ( 2 ): a = 1168.05(6), b = 717.06(4), c = 3093.40(10) pm, β = 101.202(4)°, V = 2541.6(2) · 10⁶ pm³, space group P2₁/n;[Me₃N–(CH₂)₂–NMe₃][Sn₂I₆] ( 3 ): a = 695.58(4), b = 1748.30(8), c = 987.12(5) pm, β = 92.789(6)°, V = 1199.00(11) · 10⁶ pm³, space group P2₁/c;[Fe(dmf)₆][SnI₃]₂ ( 4 ): a = 884.99(8), b = 1019.04(8), c = 1218.20(8) pm, α = 92.715(7), β = 105.826(7), γ = 98.241(7), V = 1041.7(1) · 10⁶ pm³, space group P1;(Pr₄N)[SnI₃] ( 5 ): a = 912.6(2), b = 1205.1(2), c = 1885.4(3) pm, V = 2073.5(7) · 10⁶ pm³, space group P2₁2₁2₁.     

Condensation of o-aminophenol and α-dicarbonyl compounds. Part 2. Dibenzoxazolines

The study of 2′-aryl-2,2′-dibenzoxazolines (II), obtained together with 2-hydroxy-(2H)-1,4-benzoxazines (1) by condensation of o-aminophenol with a series of phenylglyoxal derivatives, emphasized that these compounds are an equilibrium mixture of dibenzoxazolines and related tautomeric ketimine forms. This behaviour was widely investigated by ir, uv and pmr spectroscopy. J. Heterocyclic Chem., 14, 957 (1977)     

Two‐Dimensional Networks of [AuCl4]– and [AuBr4]– Anions

Several salts of protonated amines and aza‐aromatics with [AuCl₄]^– and [AuBr₄]^– anions contain two‐dimensional (“square”) anionic networks that display short halogen ··· halogen contacts. The Au₄ quadrilaterals formed by neighboring anions of the networks are to a good approximation squares, with sides of around 7.5 Å for tetrachloridoaurates and 8 Å for tetrabromidoaurates.     

Über K2PbO3 [1,2] Rb2PbO3 [3–5] und Cs2PbO3 [6,7]

On the Oxides A₂PbO₃ (A = K, Rb, Cs) The oxides A₂PbO₃ (A = K, Rb, Cs) have been reinvestigated [four-circle diffractometer PW 1100 (Fa. Philips), all particles ?anisotropically”? refined, parameters see text]. The structural features are confirmed, whereas the results on space group and parameters have to be partially corrected.     

Cyclometalated Arylazo Compounds. Part 4. ortho-cyano-1-arylazonaphthalenes and 3-amino-2-arylbenzo [g]indazoles from cyclopalladated 1-arylazonaphthalenes. 4th communication on compounds with a metal-arene σ-bond

The reaction of a cyclopalladated 1-arylazonaphthalene with tetrabutylammonium cyanide leads to an ortho-cyano-1-arylazonaphthalene and a 3-amino-aryl-benzo[g]indazole, depending upon whether triphenylphosphine or 1,2-bis(diphenyl-phosphino)ethane (DIPHOS) is used to monomerize the binuclear Pd(II)-complex. In a similar insertion reaction with cyclohexyl isocyanide the corresponding 3-(N-cyclohexyl)-aminoindazole is formed. A Pd(II)-isocyano complex is shown to be a possible intermediate in that conversion.     

Regio‐ and stereoselective synthesis of 1‐benzopyrano[2,3‐b]pyrrolo[2,3‐d]pyridines: A microwave‐accelerated intramolecular [3+2] cycloaddition reaction of azomethine ylide

Regio‐ and stereoselective syntheses of tetracyclic compounds having chromone, pyrrolidine, and piperidine rings have been accomplished by an intramolecular [3+2] cycloaddition reaction involving azomethine ylide. The reactions were carried out thermally as well as by irradiation with microwave. The latter process accelerates the reaction. The selectivities were investigated by density functional theory computation. J. Heterocyclic Chem., (2011).