Crystal structure of a mono-bridged calix[4]arene.

The title compound, 5(2)-[(5-bromo-pent-yl)-oxy]-1(2),1(14),3(5),5(5)-tetra-tert-butyl-1(7),1(8),1(9),1(10)-tetra-hydro-1(6) H,1(16) H-1(4,12)-dibenzo[b,e][1,7]dioxa-cyclo-dodecina-3,5(1,3)-dibenzena-cyclo-hexa-phan-3(2)-ol, C54H73BrO4, was synthesized from the reaction of tert-butyl-calix[4]arene with 1,5-di-bromo-pentane using K2CO3 in CH3CN. The structure consists of a calixarene unit with a five-carbon bridge connecting two proximal phenolic O atoms, and with a bromo-pent-oxy chain on one of the remaining phenolic O atoms. The calixarene unit was found to have a flattened cone conformation with no solvent (or other guest) mol-ecule observed in the cavity. Two of the opposite phenyl rings lean outwards with fold angles of 136.2 (1) and 133.0 (1)° between the rings and the plane of the bridging methyl-ene C atoms, while the other two opposite rings form fold angles of 83.27 (9) and 105.46 (9)°. There is considerable disorder in this mol-ecule. One of the tert-butyl groups is disordered over two conformations with occupancies of 0.527 (5) and 0.473 (5). The bromo-pent-oxy chain is disordered over three configurations with occupancies of 0.418, 0.332 and 0.250. The five-carbon bridge connecting two proximal phenolic O atoms is disordered over two conformations with occupancies of 0.537 (7) and 0.463 (7).

Calixarene-based mol-ecular capsule from olefin metathesis.

The reaction of tetra-kis-(all-yloxy)calix[4]arene with the first-generation Grubbs catalyst, followed by catalytic hydrogenation, gave the novel bis-calixarene 15,20,46,51,64,69,74,79-octa-oxatridecacyclo[32.28.8.8(3,28).1(13,53).1(22,44).0(9,14).0(21,26).0(38,70).0(40,45).0(52,57).0(59,63).0(7,80).0(32,73)]octa-conta-1(63),3,5,7(80),9(14),10,12,21,23,25,28(73),29,31,34,36,38(70),40,42,44,52,54,56,59,61-tetra-cosa-ene benzene monosolvate, C72H72O8·C6H6. The structure consists of two calix[4]arene units connected by four-carbon chains at each of the four O atoms on their narrow rims, to form a cage. Each of the calix[4]arene units has a flattened cone conformation in which two of the opposite aryl groups are closer together and nearly parallel [dihedral angle between planes = 7.35 (16)°], and the other two aryl groups are splayed outward [dihedral angle between planes = 72.20 (8)°]. While the cavity contains no solvent or other guest mol-ecule, there is benzene solvent mol-ecule in the lattice. Two of the alkyl linking arms were disordered over two conformations with occupancies of 0.582 (3)/0.418 (3) and 0.33 (4)/0.467 (4). They were constrained to have similar metrical and thermal parameters.

A bis-calixarene from olefin metathesis.

A ring-closing olefin metathesis reaction of tetra-kis-(all-yl-oxy)calix[4]arene gave the bis- calixarene, (15E,40E,60E)-65,74-bis-(prop-2-en-1-yl-oxy)-13,18,38,43,58,63-hexa-oxado-deca-cyclo-[28.26.8.7(20,36).1(11,45).1(51,55).0(5,57).0(7,12).0(19,24).0(26,64).0(32,37).0(44,49).1(68,72)]tetra-hepta-conta-1,3,5(57),7,9,11,15,19(24),20,22,26,28,30(64),32,34,36,40,44(49),45,47,51,53,55(65),60,68,70,72(74)-hepta-cosa-ene, C(74)H(68)O(8). It is a cage formed from two calix[4]arene units joined by butenyl groups at three of the O atoms on the narrow rim. The fourth O atom on each calixarene unit is joined with an allyl group. Each of the calix[4]arene units has a flattened cone conformation in which the all-yloxy-substituted aryl group and the opposite aryl group are close together and almost parallel [dihedral angle between planes = 1.09 (11)°], and the other two aryl groups are splayed outward [dihedral angle between planes = 79.53 (11)°]. No guest mol-ecule (e.g. solvent) was observed within the cage. The alkene C atoms of one of the links between the calixarene moieties are disordered over two orientations with occupancies of 0.533 (9) and 0.467 (9).

Hepatitis B virus infection among people attending the voluntary counselling and testing centre and anti-retroviral therapy clinic of St Paul's General Specialised Hospital, Addis Ababa, Ethiopia.

OBJECTIVE: To determine the prevalence of hepatitis B virus (HBV) infection and its risk factors among people attending the HIV voluntary counselling and testing (VCT) centre and anti-retroviral therapy (ART) clinic at St Paul's General Specialised Hospital. METHODS: A cross-sectional study was carried out on consecutive attendees from 24 January 2007 to 15 February 2007. Blood samples and data on sociodemographic and HBV risk factors were collected from 620 individuals (384 VCT and 236 HIV-infected ART clinic clients). Sera were screened for hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti-HBc) and hepatitis B e antigen (HBeAg). RESULTS: The prevalence of HBsAg and anti-HBc in VCT clients was 5.7% and 44.8%, respectively. Among HIV-infected persons, 3.9% were seropositive for HBsAg. There was no significant difference in HBsAg or anti-HBc seropositivity between HIV-positive and HIV-negative subjects. Anti-HBc positivity was significantly higher in men, in the age range 40-49 years, and in subjects with a history of catheterisation. CONCLUSION: This study shows a high prevalence and similar distribution of HBV infection in HIV-positive and HIV-negative people. However, with the emphasis given to HIV-positive cases, screening for HBV infection is important.