A Concise Synthesis of 2‐Amino‐1,2,3,4‐tetrahydronaphthalene‐6,7‐diol (‘6,7‐ADTN’) from Naphthalene‐2,3‐diol

2‐Amino‐1,2,3,4‐tetrahydronaphthalene‐6,7‐diol ( 2 ; 6,7‐ADTN) was synthesized starting from naphthalene‐2,3‐diol in seven steps and with an overall yield of 44%. Methylation of naphthalene‐2,3‐diol with dimethyl sulfate, followed by Friedel? Crafts acylation with AcCl, gave 2‐acetyl‐6,7‐dimethoxynaphthalene. 2‐Acetyl‐6,7‐dimethoxynaphthalene was converted to 6,7‐dimethoxynaphthalene‐2‐carboxylic acid by a haloform reaction. Birch reduction of the carboxylic acid with 4 mol‐equiv. of Na in liquid ammonia afforded 1,2,3,4‐tetrahydro‐6,7‐dimethoxynaphthalene‐2‐carboxylic acid, from which 2 was obtained by a Curtius reaction, followed by hydrogenolysis and demethylation.     

1,17‐Hepta­decane­diol

In the title compound, C₁₇H₃₆O₂, one of the hydroxyl groups has a gauche conformation with respect to the hydro­carbon skeleton, which is all‐trans, whereas the other has a trans conformation. The molecular shape is rod‐like and the compound has a rotator phase in which mol­ecules are assured greater motional freedom, as in liquid crystals. In addition, the mol­ecules arranged along the longest axis, b, form layers which are very similar to those of the smectic A liquid crystals.     

1,15‐Penta­decane­diol

In the title compound, C₁₅H₃₂O₂, one of the terminal hydroxyl groups has a gauche conformation with respect to the hydro­carbon skeleton, while the other is trans. The mol­ecules lie parallel to the longest axis and form layers similar to those of the smectic A structure of liquid crystals. These features are similar to those of the homologues with an odd number of C atoms, but different from those with an even number.     

Naphthalene‐1,5‐diammonium bis[trifluoridostannate(II)]

The structure of the title compound, (C₁₀H₁₂N₂)[SnF₃]₂, is made up of alternating layers of cations and anions, where the anion layers form extended polymeric sheets through a series of secondary Sn...F bonds. Strong N—H...F hydrogen bonds crosslink adjacent cation and anion layers, thereby building a three‐dimensional network.     

A general synthesis of 8‐hydroxy‐6‐substituted‐1,7‐naphthyridines

A general method for the synthesis of 8‐hydroxy‐6‐substituted‐1,7‐naphthyridines is described using acylation of the dianion derived from tert‐butylamide 1 , followed by cyclization of the resulting intermediate ketones 2 with ammonium acetate.     

Synthesis of (±)‐Trinervitadiene‐2,3‐diol

The first synthesis of trinervita‐1(15),8(19)‐dien‐2β,3α‐diol ( 2a ) and its 2α‐isomer 2b , which have been isolated from termite soldiers, where they are used as defense chemicals, is documented starting from geranylgeranioic acid in 33 steps. The route for construction of the key intermediate of the trinervitane skeleton 8 has been developed previously (Scheme 1). Noteworthy features include the efficient construction of the trinervitane framework from the corresponding bicyclic 7(16)‐secotrinervitane skeleton and Me₃SiCl (TMSCl)‐induced ring‐opening of tetrasubstituted epoxide to give the corresponding allyl alcohols (Scheme 7). The synthetic route developed in the present study seems applicable to the syntheses of other trinervitane‐type natural products.     

Cocrystals of 2,3,5,6‐tetrafluorobenzene‐1,4‐diol with diaza aromatic compounds

2,3,5,6‐Tetrafluorobenzene‐1,4‐diol easily forms cocrystals with heteroaromatic bases containing the pyrazine unit. In the 1:1 complexes with pyrazine, C₆H₂F₄O₂·C₄H₄N₂, (I), and quinoxaline, C₆H₂F₄O₂·C₈H₆N₂, (II), the crystal components are linked via O—H...N hydrogen bonds into one‐dimensional chains. With the largest base, phenazine, the 1:2 benzenediol–phenazine complex, C₆H₂F₄O₂·2C₁₂H₈N₂, (III), was obtained, with the molecules linked via O—H...N interactions into a discrete heterotrimer. In all three cocrystals, the two types of molecules are organized into layers via softer C—H...O and C—H...F interactions and π–π stacking interactions, with stronger hydrogen bonds linking molecules of adjacent layers. In (II) and (III), molecules are arranged into heterostacks, whereas in (I) separate stacks are formed by the heterocyclic base and the benzenediol molecule.     

Enantiotropic phase transition and twinning in 2,2,3,3,4,4‐hexafluoropentane‐1,5‐diol

Four crystal structure determinations of 2,2,3,3,4,4‐hexafluoropentane‐1,5‐diol (HFPD), C₅H₆F₆O₂, were conducted on a single specimen by varying the temperature. Two polymorphs of HFPD were found to be enantiotropically related as phases (I) and (II), both in the space group P1. These structures contain closely related R₄⁴(20) sheets. A structure determination was completed on form (Ia) at 283 K. Form (Ia) was then supercooled below the phase transition temperature at 279 to 173 K to give form (Ib) for a second structure determination. Metastable form (Ib) was transformed by momentary warming and recooling to give form (II) for a third structure determination at 173 K. Form (II) transformed to form (Ic) upon warming to 283 K. Enantiotropic phase transitions between phases (I) and (II) were confirmed with X‐ray powder diffraction and differential scanning calorimetry. Form (Ia) was found as a twin by nonmerohedry by a reflection in (011). This twinning persists in all phases described. Additional twinning was found after the phase (I) to phase (II) transformation. These two additional twin components are related to the first pair by a 180° rotation about the (012) plane. This latter pair of twins persisted as the specimen was warmed back to form (Ic) at 283 K.     

The complex packing pattern of cis‐1,2‐dimethylcyclobutane‐1,2‐diol

cis‐1,2‐Dimethylcyclobutane‐1,2‐diol, C₆H₁₂O₂, crystallizes with five molecules in the asymmetric unit. Of these, two molecules are the building blocks of columns with a complex hydrogen‐bonding pattern in their hydrophilic core. The walls of the columns are formed by the lipophilic parts of the molecules. The remaining three molecules of the asymmetric unit build columns with a less complex hydrogen‐bonding system. In terms of co‐operativity, the most significant feature is the formation of homodromic rings of six hydroxy functions.     

Naphthalene‐1,6‐diol: a three‐dimensional framework built from O—H...O,O—H...π and C—H...O hydrogen bonds

The asymmetric unit of the title compound, C₁₀H₈O₂, contains two practically planar symmetry‐independent molecules linked by one O—H...O hydrogen bond. Molecules are further linked into a three‐dimensional network, which is built from R₆⁶(36), R₆⁶(18), R₆⁶(30) and R₄⁴(26) rings formed by the combined effect of three O—H...O and one C—H...O hydrogen bond. This network is additionally stabilized by an O—H...π interaction.     

Stereoselective Total Synthesis of (3S,5S)‐1,7‐Bis(4‐hydroxyphenyl)heptane‐3,5‐diol, (3S,5S)‐Alpinikatin,and Its Diastereoisomers

Stereoselective synthesis of the diarylheptanoids, (3S,5S)‐1,7‐bis(4‐hydroxyphenyl)heptane‐3,5‐diol ( 1 ), (3S,5S)‐alpinikatin ( 3 ), and their diastereoisomers ( 2 and 4 , resp.), was achieved from readily available 4‐hydroxybenzaldehyde. The synthetic sequences involve Browns's allylation and Et₂Zn mediated diastereoselective alkynylation reaction as key steps.     

Cyclo[bis(1,7‐naphthylenedialkylamidophosphites)]

The possibility of regioselective cyclobisphosphorylation of nonsymmetrical bisphenols was shown for the 1,7‐dihydroxynaphthalene–phosphorous acid triamide system. The structure and essential chemical properties of the first nonsymmetrical phosphacyclophane were studied. New data demonstrating peculiar features of bisphenol diamidophosphites were obtained. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:404–412, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10143     

Synthesis and characterization of soluble polyimides derived from [1,1′;4′,1″]terphenyl‐2′,5′‐diol and biphenyl‐2,5‐diol

Two series of polyimides based on laterally attached p‐terphenyl and biphenyl groups were synthesized. The solubility and thermal properties were studied using DSC, thermogravimetric analysis, and the solubility test. These polymers exhibited good thermal stability and excellent solubility. The high solubility for both polymer series was attributed to the non‐coplanarity of diamine monomers and the use of fluorinated dianhydride, whereas the slightly better solubility for polymers based on p‐terphenyl was attributed to further weakening of interchain interaction of the polymers. Both polymer series exhibited glass‐transition temperatures (T_g's) in the range of 244–272 °C. The T_g's of polymers containing laterally attached p‐terphenyls were higher than those of their counterparts containing biphenyls by 5–17 °C. This was attributed to the formation of an interdigitated structure that hinders the segmental movement of polymer chains. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2998–3007, 2001     

1,6‐ and 1,7‐naphthyridines. IV. Synthesis of hydroxycarboxamide derivatives

A series of 8‐hydroxy‐1,6‐naphthyridin‐5(6H)‐one‐7‐carboxamides 1 and the isomeric 5‐hydroxy‐1,7‐naphthyridin‐8(7H)‐one‐6‐carboxamides 2 were synthesized. N‐Lactam unsubstituted compounds 1a‐c and 2a,b were obtained by alkoxide‐induced rearrangement of the corresponding quinolinimidoacetamides 3 . Compounds 1e,f and 2e,f were synthesized by heterocyclization of the corresponding quinolinamic esters 6 and 7 . Spectroscopic properties (uv, ir, ¹H and ¹³C nmr and ms) were analyzed and the proposed structures confirmed.     

On the Reaction of Glycerol Dehydratase with But‐3‐ene‐1,2‐diol

Intriguing inactivation : Calculations suggest that the ability of relatively high‐energy radical intermediates to inactivate glycerol dehydratase (GDH) may reflect a general and hitherto unidentified inactivation mechanism in the reaction of coenzyme B₁₂‐dependent enzymes and 3‐unsaturated 1,2‐diols (see scheme; AdoCbl: adenosylcobalamin or coenzyme B₁₂).

     

Divergent Gold(I)‐Catalyzed Skeletal Rearrangements of 1,7‐Enynes

The gold(I) complex catalyzed cycloisomerization and skeletal rearrangement of 1,n‐enynes (n=5–7) is a powerful methodology for the efficient synthesis of complex molecular architectures. In contrast to 1,6‐enynes, readily accessible homologous 1,7‐enynes are largely unexplored in such transformations. Here, the divergent skeletal rearrangement of all‐carbon 1,7‐enynes by catalysis with a cationic gold(I) complex is reported. Depending on electronic and steric factors, differently substituted 1,7‐enynes react via different carbocations formed from a common gold carbene intermediate to yield on the one hand novel exocyclic allenes and on the other hand tricyclic hexahydro‐anthracenes through a novel dehydrogenative Diels–Alder reaction.     

UV‐responsive degradable polymers derived from 1‐(4‐aminophenyl) ethane‐1,2‐diol

A UV‐responsive polymer was prepared via condensation polymerization of 2‐nitrobenzyl(4‐(1,2‐dihydroxyethyl)phenyl)carbamate and azalaic acid dichloride. When the polymer was irradiated with UV light, the nitrobenzyl urethane protecting group was removed and the deprotected aniline underwent spontaneous 1,6‐elimination reactions, resulting in degradation of the polymer. Nanoparticles with encapsulated Nile Red were formulated with the degradable polymer and triggered burst release of Nile Red was observed when the nanoparticles were irradiated by UV light. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1161–1168