The Career Costs of Children

This paper analyzes the life-cycle career costs associated with child rearing and decomposes their effects into unearned wages (as women drop out of the labor market), loss of human capital, and selection into more child-friendly occupations. We estimate a dynamic life-cycle model of fertility, occupational choice, and labor supply using detailed survey and administrative data for Germany for numerous birth cohorts across different regions. We use this model to analyze both the male-female wage gap as it evolves from labor market entry onward and the effect of pro-fertility policies. We show that a substantial portion of the gender wage gap is explainable by realized and expected fertility and that the long-run effect of policies encouraging fertility are considerably lower than the short-run effects typically estimated in the literature.fertility, labor supply, occupational choice

Synthesis of novel urethanes from a castor oil derived C22-acyloin

The synthesis of new bio-based chemical building blocks, resulting from the condensation of a renewable C-22 acyloin derived from non-edible castor oil, with mono- and bifunctional isocyanates is reported. The condensation with aliphatic mono-isocyanates was relatively straightforward, however phenyl isocyanates only resulted in low yields together with the formation of a cyclic hemi-aminal during purification. The condensation with diisocyanates was successful for the aliphatic hexamethylene diisocyanate. As for the aromatic 2,4-toluene diisocyanate, a low yield of the desired product was obtained, since a similar ring closing reaction took place. The urethanes were synthesized in order to evaluate their plasticizing and viscosity-modifying properties

Modelling of Lewis-Acid Catalyzed Ring Opening of Oxanorbornenes in the Synthesis of Azaheterocyclic Phosphonates

Since the discovery of the biological activity of aminophosphonates, research started on the synthesis of more constraint azaheterocyclic phosphonates. We developed a route via an intramolecular Diels-Alder reaction towards α-aminophosphonates 1. The obtained oxanorbornene skeleton is a valuable synthetic intermediate that has been used in various natural product syntheses. An important synthetic transformation involves the cleavage of the oxygen bridge, used to construct substituted arenes and cyclohexenes. We wanted to investigate the ring opening of adducts 1 using different Lewis acids experimentally and to get more insight in the reaction pathways towards the different products via molecular modelling. In this presentation the results obtained with TiCl4 and FeCl3 catalyst are shown. One of the difficulties in studying transition metal catalysts is the determination of their proper spin state. The tetrahedral TiCl4 monomer has spin zero. The FeCl3 catalyst has a high-spin ground state. It prefers a half-filled d-shell and has multiplicity 6. The complexation of the Lewis acids with different binding sites was investigated at a B3LYP level of theory with a LanL2DZ pseudopotential for the transition metals. Bidentate coordination towards the most electronegative phosphonate oxygen and the oxygen bridge is favoured for both catalysts. The reaction pathways were evaluated at a TPSSh and a B3LYP level of theory. The role of dispersion interactions was evaluated using the Van der Waals correction term from B3LYP-D. The energy barrier for breaking the C-O bond with FeCl3 is larger than with TiCl4. This corresponds with the experimental observation that the titanium catalyzed reaction completes at 0°C and the reaction with the iron catalyst requires reflux conditions in CH2Cl2. The main difference between the TiCl4 and FeCl3 as Lewis acids in the opening of the oxanorbornene oxygen bridge is their way of stabilizing the oxide anion. When the C-O bond is broken, the bond between the alkoxide anion and the transition metal tightens. With TiCl4, the alkoxide replaces a chloride that adds to the allyl cation in a concerted way. With FeCl3, however, the carbocation is stabilized by the alkoxide anion itself and no chloride transfer occurs; instead, the bond with the phosphonate is broken. A plausible further reaction path towards the experimentally observed ketone involves a 1,2-hydride shift

Synthesis and analysis of stable isotope-labelled N-acyl homoserine lactones

Aliphatic aldehydes were deuterated at the alpha-position via a base-catalyzed exchange reaction with D2O. These deuterated building blocks were used for the synthesis of labelled analogues of quorum sensing signal molecules belonging to the three major classes of naturally occurring N-acylated homoserine lactones (AHLs), with the label on a non-enolizable and therefore stable position. Besides the application of these stable isotope-labelled AHLs as a labelled standard for analysis via isotope dilution mass spectrometry, these compounds can be used to study the metabolic fate of the fatty acid tail of the AHL-molecule. These isotope-labelled compounds were fully characterized and used to synthesize the deuterated analogues of two commonly occurring AHL-degradation products, a tetramic acid and a ring opened N-acyl homoserine

Synthesis and biological evaluation of novel N-α-haloacylated homoserine lactones as quorum sensing modulators

Novel N-α-haloacylated homoserine lactones, in which a halogen atom was introduced at the α-position of the carbonyl function of the N-acyl chain, have been studied as quorum sensing (QS) modulators and compared with a library of natural N-acylated homoserine lactones (AHLs). The series of novel analogues consists of α-chloro, α-bromo and α-iodo AHL analogues. Furthermore, the biological QS activity of the synthetic AHL analogues compared to the natural AHLs was evaluated. Halogenated analogues demonstrated a reduced activity in the Escherichia coli JB523 bioassay, with the α-iodo lactones being the less active ones and the α-chloro AHLs the most potent QS agonists. Most of the α-haloacylated analogues did not exhibit a significant reduction when tested in the QS inhibition test. Therefore, these novel analogues could be utilized as chemical probes for QS structure–activity studies