ABSTRACT
N-substituted pyrido[4,3-d]pyrimidines are heterocycles which exhibit the asymmetric hydrogen bonding codes of both guanine and cytosine at 60° angles to each other, such that the molecules self-organize unambiguously into a cyclic hexamer, assembled via 18 intermolecular hydrogen bonds. The synthesis is straightforward and can be concluded in six steps from the commercially available malononitrile dimer. X-ray crystallographic analysis of the supermacrocyclic structure shows an undulating disk with a ca. 10.5 Å cavity, the centers of which do not overlap sufficiently to describe a channel in the solid state. However, AFM, SEM, and TEM imaging in solution reveals the formation of 1D nanostructures in agreement with their self-assembly into rosette supermacrocycles, which then stack linearly to form rosette nanotubes.
Subject(s)
Heterocyclic Compounds/chemical synthesis , Nanotubes/chemistry , Pyrimidines/chemical synthesis , Crystallography, X-Ray , Cytosine/chemistry , Guanine/chemistry , Heterocyclic Compounds/chemistry , Hydrogen Bonding , Models, Molecular , Molecular Structure , Particle Size , Pyrimidines/chemistry , Surface PropertiesABSTRACT
Lithium, used in conjunction with sodium metal, produces a high yield of biphenyl when reacted with dibenzothiophene, dibenzothiophene sulfoxide or dibenzothiophene sulfone.
Subject(s)
Sulfur/chemistry , Thiophenes/chemistry , Cyclization , Magnetic Resonance Spectroscopy , Oxidation-Reduction , Spectrometry, Mass, Electrospray Ionization , Spectrophotometry, InfraredABSTRACT
Lithium, used in conjunction with sodium metal, produces a high yield of carbazole when reacted with phenothiazine-5-oxide or phenothiazine-5,5-dioxide. A high yield of 9-ethylcarbazole is also produced when these reagents react with 10-ethylphenothiazine, 10-ethylphenothiazine-5-oxide, and 10-ethylphenothiazine-5,5-dioxide. Degassed Raney nickel produces carbazole in high yield when reacted with phenothiazine and phenothiazine-5-oxide. A moderate yield of 9-ethylcarbazole is produced when n-butyllithium is reacted with 10-ethylphenothiazine-5-oxide.
Subject(s)
Phenothiazines/chemistry , Carbazoles/chemical synthesis , Lithium , Nickel , SulfurABSTRACT
Molecules which possess the hydrogen bonding codes of both guanine and cytosine ("G-C DNA base hybrids") are known to organize in a hexagonal array both in solution and the solid state. Including an easily derivatizable functional group in the molecule allows the co-organization of virtually any species in the hexagonal periphery. Simple 5- and 6-step procedures are described for the synthesis of DNA base hybrids with tail groups which are terminated by electrophilic (primary bromide) and nucleophilic (primary alcohol) functions, respectively.
