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The electrophilic amination of carbanions allows the preparation of a wide range of amines through an unconventional C−N bond‐forming reaction. The concepts behind the varied synthetic approaches, classified by the nature of the aminating agent and of the organometallic species, are discussed. The mild operational conditions, the high selectivity, and the availability of the starting materials are good assets of these processes which nicely complement each other. New appealing and flexible routes can be devised, leading in several cases to the synthesis of otherwise not easily accessible N‐containing compounds.

A new diamine, N,N'-diphenyl-N,N'-bis-biphenyl-(1,1'-biphenyl)-4,4'-diamine (PTPD), has been synthesised to be applied as a hole-transporting material for multilayer organic light-emitting diodes (LEDs). Electrical and optical characteristics of a series of double-layer (DL) LEDs using PTPD as hole-transporting layers (HTL) and Alq3 and Znq2 as electron-transporting layers have been measured and compared with those for DL LEDs based on other HTLs (TPD and NTPD). The differences are discussed in terms of charge injection at the electrodes and electron–hole recombination processes at the organic interfaces. The prerequisites based on the molecular structure of the compound, confirmed by preliminary experimental observations, suggest PTPD to be a stable hole-transporting material for high-durability organic LEDs. Copyright © 2000 John Wiley & Sons, Ltd.

We evaluated T-cell mediated lymphokine activated killer (LAK) function during the late (greater than 5 months) reconstitution phase after T cell-depleted allogeneic bone marrow transplantation (BMT) for hematologic malignancy. Since LAK cells are sustained by interleukin-2 (IL-2), we also investigated the ability of post-BMT T cells to produce IL-2. These functions were investigated at the clonal level. More than 200 T-cell clones from six long-term BMT recipients were generated and compared with 60 T-cell clones derived from two normal controls. Almost all the CD8+ clonal cultures from BMT recipients expressed cytolytic activity in a lectin-dependent cellular cytoxicity assay. Interestingly, a higher proportion of BMT recipient-derived cytolytic clones were able to mediate LAK activity in comparison with control clones (28% versus 4%, P less than .05). However, T-cell clones from BMT recipients, as opposed to control clones, were largely incapable of producing IL-2. Given the high proportions of post-BMT circulating CD8+ T cells, it appears that, in long-term BMT recipients, the precursors of nonspecific LAK effectors are present at above normal levels. However, their function may be defective in vivo due to poor IL-2 production.

T cells recovering after bone marrow transplantation (BMT) were analyzed for their phenotypic and functional features by two-color immunofluorescence and a high efficiency cloning technique. A predominance of cells co-expressing natural killer (NK)-related surface antigens, such as Leu 7 (CD57) and CD11b, was detected within both the CD4+ and CD8+ subsets from 5 months postgrafting onward. Such cells are virtually absent among normal circulating CD4+ cells and account for a minority (approximately 30%) of normal CD8+ cells. Postgrafting T cells representative of the whole range of NK-related antigen co-expression were selected from six patients for clonal analyses. In control subjects, 63% and 41% of the CD4+ and CD8+ clones, respectively, produced interleukin-2 (IL-2) whereas approximately 30% of either CD4+ or CD8+ control clones produced interferon (IFN)-gamma. At variance, and irrespective of their CD4+/CD8+ phenotype, lower proportions of BMT recipient-derived clones produced IL-2 (20% and 12%, respectively), whereas the majority of both CD4+ and CD8+ clones (75% and 71%, respectively) released high amounts of IFN-gamma. Purified populations of CD57+/CD11b+ v negative cells from two BMT recipients and two control subjects were cloned and subsequently evaluated for IL-2 and IFN-gamma production. CD57+/CD11b+ cell-derived clones were poor IL-2 producers in both normal subjects and BMT patients. In contrast, IL-2- producing clones were frequent (62% to 79%) among those derived from CD57-/CD11b- cells from normal subjects, whereas they were still represented at lower than normal proportions, ie, 25% to 41%, among clones generated from BMT recipients. CD57+/CD11b+ cells gave rise to comparably high proportions of IFN-gamma producing clones in both normal subjects and BMT recipients (approximately 80%). In contrast, IFN-gamma producing clones were approximately 25% to 50% of CD57-/CD11b- cell-derived clones in both normal subjects and BMT patients. Therefore, while the predominance of NK-related antigen-positive T cells may be predictive of poor IL-2 and high IFN-gamma production, the immune derangement in long-term BMT recipients is further enhanced by the finding that all T cells may be poor IL-2 producers. It is also suggested that IL-2 production is a preferential function of T cells that do not express CD57 and CD11b, whereas IFN-gamma production is attributable to T cells that express CD57 and CD11b.

A recent study1 of the reactivity (H-D base-catalyzed exchange) of diastereotopic α sulfonium protons, CαCα, S+-C(HaHb)-, has suggested an important geometrical factor contributing to the stability of the quasi-ylide transition state. This is the syn or anti alignment of the incipient lone pair orbital with one of the adjacent S+-Cα bonds. Thus, for example, of the ylides derived from A, a rigid sulfonium precursor, B (lone pair anti to Cα) appears to be more stable than C (lone pair gauche to both Cα and Cα). A MO study suggests the stabilizing factor in question is due to the [image omitted] orbital interaction between the lone pair group orbital and the σ* group orbital of the adjacent S+-Cα bond, the interaction being at a maximum when the orbitals involved are either syn or anti coplanar.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The reaction between the lithiated sulfides or nitriles (I) and bis(trimethylsilyl) peroxide (II) affords the title compounds, i.e. the trimethylsilyloxy derivatives (III).

The acyl chlorides (I), as well as the diacid dichlorides (IV) and (VI) react with (trimethylsilyl)cuprate, generated in situ from (trimethylsilyl)lithium (II) and CuCN, to give the acylsilanes (III), (V), and (VII).

Sodium hexamethyldisilazide (I) is coupled with chloromethyl methyl sulfide (II) to yield the bis(silyl)methylthiomethylamine (III).

Pummerer reaction of tris(trimethylsilyl)methylthio methane (I) yields the bis(trimethylsilyl)ketone (II) and the dithioacetal (III).