The relationship between the physical chemistry and biology of self-assembly is poorly understood, but it will be critical to quantitatively understand infection and for the design of antivirals that target virus genesis. Here we take advantage of heteroaryldihydropyrimidines (HAPs), which affect hepatitis B virus (HBV) assembly, to gain insight and correlate in vitro assembly with HBV replication in culture. Based on a low-resolution crystal structure of a capsid-HAP complex, a closely related series of HAPs were designed and synthesized. These differentially strengthen the association between neighboring capsid proteins, alter the kinetics of assembly, and give rise to aberrant structures incompatible with a functional capsid. The chemical nature of the HAP variants correlated well with the structure of the HAP binding pocket. The thermodynamics and kinetics of in vitro assembly had strong and predictable effects on product morphology. However, only the kinetics of in vitro assembly had a strong correlation with inhibition of HBV replication in HepG2.2.15 cells; there was at best a weak correlation between assembly thermodynamics and replication. The correlation between assembly kinetics and virus suppression implies a competition between successful assembly and misassembly, small molecule induced or otherwise. This is a predictive and testable model for the mechanism of action of assembly effectors.Hepatitis B virus (HBV), which chronically infects approximately 400 million people and contributes to 1 million deaths per year, is an enveloped virus with an icosahedral core. The core is assembled in the cytoplasm from core (capsid) protein, viral pregenomic RNA, viral reverse transcriptase, and a few host proteins. The core plays indispensable roles in viral DNA synthesis from the pregenome and intracellular trafficking (10). The predominant antiviral strategy against HBV is to attack the reverse transcriptase. Unsurprisingly, HBV reverse transcriptase inhibitors lead to drug-resistant mutants in HBV (7,24,30) and also human immunodeficiency virus (14). Resistance can have broader consequences because of the extensive gene overlap in HBV, since some reverse transcriptase mutations lead to surface protein that is insensitive to antibodies generated by the HBV vaccine (25). An alternative therapeutic strategy would be targeting capsid assembly (15, 33). Heteraryldihydropyrimidines (HAPs), first identified by scientists at Bayer AG as having anti-HBV activity in a cell culture-based screen, act in a capsid protein-specific manner (8,11,(19)(20)(21)(22).The mechanism of HAP activity has been studied in vitro using the 149-residue assembly domain of the HBV capsid protein, Cp149, which is always found as a homodimer (11,21,22). Assembly of empty capsids is nucleated by slow formation of a trimer of dimers followed by rapid addition of subsequent dimers (34). We previously reported that HAP 1 (Fig. 1), a variant of the original HAP structure identified by the Bayer laboratory (8,20), increases the rate of assembly by...

The cross-coupling of Baylis-Hillman acetate adducts and bis(pinacolato)diboron proceeds readily in high yields in the presence of palladium catalyst to produce 3-substituted-2-alkoxycarbonyl allylboronates. These allylboronates can be transformed to stable allyl trifluoroborate salts by addition of excess aqueous KHF2. Both the allylboronate and allyltrifluoroborate derivatives react with aldehydes to afford functionalized homoallylic alcohols stereoselectively.

[reaction: see text] The direct coupling of aryl- and vinylboronic acids with allylic alcohols has been achieved in ionic liquids using a rhodium catalyst.

[reaction: see text] The cross-coupling of potassium organotrifluoroborates and acetates of Baylis-Hillman adducts proceeds readily in moderate to excellent yield in the presence of Pd(OAc)(2). The reaction tolerates hindered trifluoroborate salts, and the process is stereoselective.

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