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"Lone Remember pair-assisted ionization." Name_______________________________ 215 F07-Exam No. 1 Page 2 I. (20 points) The following compounds are those used in our study on the enzymatic transformation of cholesterol to pregnenolone. 1) Designate in each of the boxes below the stereochemistry (R or S) at the indicate carbon center and 2) provide in each of the boxes provided the formal oxidation number of each of the indicated carbon atoms in pregnenolone. 1) stereochemistry (R or S) of the designated carbon centers: R or S? H 2 R or S? OH H H H 2 R or S? OH H H H H HO H H 2 HO OH H H R or S? 2 H HO H H HO O H H H HO H H 2) oxidation numbers of the designated carbon atoms: oxidation #: O 2 oxidation #: 2 R or S? 2 H H H H oxidation #: 2 oxidation #: 2 oxidation #: 2 HO pregnenolone II. (10 points) Write in the boxes below the expected hybridization of each of the indicated atoms (i.e., sp3, sp2, or sp) in the following molecules. hybridization: 2 hybridization: hybridization: 2 2 hybridization: H N H O O O N H H 2 hybridization: 2 III. (10 points) For each of the following pairs of compounds, predict which compound is more acidic. Compare the two underlined Hs for each pair and circle the compound that is more acidic for each pair. (1) a. (H3C)3CO-H (2) a. F3CCH2O-H O-H b. H3CCH2O-H b. H3CCH2O-H O-H 2 (4) a. O H b. H3CO O H 2 2 (5) 2 a. O H (3) a. O b. O b. O N O O H 2 Remember "Lone pair-assisted ionization." Name______________________________ 215 F07-Exam No. 1 Page 3 IV. (22 points) Dimethyl tartrate is widely used as a versatile starting compound in synthesis. In most of its application, the first step is the protection of the diol in dimethyl tartrate as its ketal. For example, treatment of dimethyl tartrate with excess cyclopentanone in the presence of a catalytic amount of p-toluenesulfonic acid (p-TsOH; pKa -0.51) results in the formation of its cyclopentylidene derivative shown below. Draw the structure of the expected hemiketal intermediate and propose in the box below a curved-arrow reaction mechanism for this transformation from the diol to the cyclopentylidene ketal. You may use H-B and B- for the acid p-TsOH and its conjugate bas, respectively. You do not need to balance each step. O H3CO H3CO O OH + OH O H-B H3CO H3CO O O O + O H2O cyclopentylidene cyclopentanone (ketal) dimethyl tartrate derivative (i) Draw the mechanism through the formation of the hemiketal intermediate. O O H3CO H3CO O OH OH (ii) Draw the mechanism through the formation of the ketal product. hemiketal intermediate O H3CO H3CO O O O ketal product Remember "Lone pair-assisted ionization." - Name_______________________________ 215 F07-Exam No. 1 Page 4 V. (12 points) 1) Azide ion ( N3) is an excellent nucleophile that displaces a leaving group from primary and secondary alkyl halides and sulfonates. Show in the box provided below three major resonance forms of azide ion in Lewis structures. 6 2) In a recent publication (Org. Lett. 2007, 9, 4069), azide ion was employed in order to stereospecifically introduce a nitrogen group as shown below. Provide in the box below the structure of the expected product from the following two-step reaction. Make sure to indicate its stereochemistry. HO 1. MsCl N(CH2CH3)3 CH2Cl2 0 C 2. NaN3 DMF (solvent) 80 C C15H20N4 6 N VI. (12 points) Complete the following reaction scheme by providing the structures in each of the three boxes below (Synlett 2007, 2584). O Ph N Cl OH 1. Cl Cl O CH2Cl2 2. N(CH2CH3)3 4 H3CC(=O)OH (acetic acid) ClCH2CH2Cl (solvent) ! (heat) O S PhNH2 Ph ! K-OC(CH3)3 N Cl H Ph N NaBH[OC(=O)CH3]3 imine 4 + H2O 4 + KCl + HOC(CH3)3 Remember "Lone pair-assisted ionization." Name_______________________________ 215 F07-Exam No. 1 Page 5 VII. (18 points) Complete the following reaction schemes by providing in the boxes the structures of the corresponding products. Make sure to indicate the stereochemistry and, where applicable, label isotopes. 1). My work from the last century! CH3ONa CH3OH O H insect juvenile hormone 4 O O CH3 H218O HClO4 (catalytic) 0 C 4 2) [Eur. J. Chem. 2005, 4929] Br O O Mg THF (solvent) 2 1. O 2. aq NH4Cl 4 H3O+, ! OH + OH C6H12O2 5-membered hemiacetal + enantiomer 4 Remember "Lone pair-assisted ionization." Name_______________________________ 215 F07-Exam No. 1 Page 6 VIII. (16 points) Complete the following reaction schemes by providing in the boxes the structures of the corresponding products. Make sure to indicate the stereochemistry where applicable. (1) O Br N O H2O dioxane (solvent) 4 + 4 (2) 1. 9-BBN 2. H2O2/H2O NaOH 4 CrO3, H2SO4 H2O, acetone 4
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Virginia Tech >> CSES >> 3134 (Spring, 2008)
Syllabus CSES 3134 Soils in the Landscape Spring Semester, 2007 W. Lee Daniels (Lecture) 244 Smyth Hall 231-7175 Office Hours: 10:30 - 12:00 T/Th wdaniels@vt.edu Matt Eick (Lab + Lect.) 236 Smyth 231-8943 3:00 4:00 T/Th eick@vt.edu Catalog Descri...
Virginia Tech >> CSES >> 3134 (Spring, 2008)
Spring 2007 - CSES 3134 Soils in the Landscape Detailed Schedule Date 1/16 1/18 1/23 1/25 1/30 2/1 2/6 2/8 2/13 2/15 2/20 2/22 2/27 3/1 3/13 3/15 3/20 3/22 3/27 3/29 4/3 4/5 4/10 4/12 4/17 4/19 4/24 4/26 5/1 5/5 (Sat.) Topic Organization & Introduct...
Virginia Tech >> CSES >> 3114 (Spring, 2008)
PARENT MATERIALS, SOIL FORMING FACTORS, AND SOIL PROFILE DESCRIPTIONS PARENT MATERIALS, SOIL FORMING FACTORS, AND SOIL PROFILE DESCRIPTIONS Let\'s start with an ideal, simplified weathering sequence - keep in mind this is just one of an infinite numb...
Virginia Tech >> CSES >> 3114 (Spring, 2008)
TYPICAL POORLY-DEVELOPED SOIL PROFILE FOUND THROUGHOUT THE This profile illustrates a typical poorly-developed soil that could be found on the mountains in the Blackburg area. First note we have the horizons O, A, B, C, and R. Then note we have three...
Virginia Tech >> CSES >> 1004 (Fall, 2008)
COLLEGE OF AGRICULTURE AND LIFE SCIENCES CHECKSHEET for a MINOR in CROP AND SOIL ENVIRONMENTAL SCIENCES offered by the Department of Crop and Soil Environmental Sciences Effective for Students Graduating 2006 (and thereafter) REQUIRED COURSES (compl...
Michigan State University >> ADV >> 201 (Fall, 2007)
Managing the Advertising Production Process Planning Organizing Specific Tasks Managed by the Producer or Production Manager Reproduction of visuals Shooting and editing of scenes Precise specification and placement of type Checking, approvin...
Indiana Wesleyan >> PHYS >> 142 (Spring, 2008)
2.2: a) The magnitude of the average velocity on the return flight is (5150 103 m) (13.5 da) (86, 400 s da) 4.42 m s . ^ The direction has been defined to be the x-direction ( i ). b) Because the bird ends up at the starting point, the average v...
Indiana Wesleyan >> PHYS >> 142 (Spring, 2008)
2.8: From the expression for x(t), x(0) = 0, x(2.00 s) = 5.60 m and x(4.00 s) = 20.8 m. a) 5.60 m 0 .8 m 2.80 m s b) 204.00 s 0 5.2 m s c) 20.8 m 5.60 m 7.6 m s 2.00 s 2.00 s ...
Indiana Wesleyan >> PHYS >> 142 (Spring, 2008)
2.43: a) Using the method of Example 2.8, the time the ring is in the air is t v0 y 2 v0 y 2 g ( y y0 ) g (5.00 m s) 2(9.80 m s 2 )( 12.0 m) (9.80 m s 2 ) 2 (5.00 m s) 2.156 s, keeping an extra significant figure. The average velocity is then 1...
Indiana Wesleyan >> PHYS >> 142 (Spring, 2008)
2.70: The position of the cars as functions of time (taking x1 = 0 at t = 0) are x1 1 2 at , 2 x2 D v 0 t. The cars collide when x1 = x2; setting the expressions equal yields a quadratic in t, 1 2 at 2 v0 t D 0, the solutions to which are t 1 a ...
Indiana Wesleyan >> PHYS >> 142 (Spring, 2008)
2.51: a) From Eqs. (2.17) and (2.18), with v0=0 and x0=0, vx x t 0 t 0 ( At Bt 2 ) dt A 2 t 2 B 3 t 3 A 2 B 2 t t (0.75 m s 3 )t 3 (0.040 m s 4 )t 3 2 3 A 3 B 4 dt t t (0.25 m s 3 )t 3 (0.010 m s 4 )t 4 . 6 12 b) For the velocity to be a maximum,...
Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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Ill. Chicago >> CHEM >> 116 (Fall, 2006)
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