(−)-N-(tert-Butoxy­carbon­yl)-L-proline-2-thio­amide (Boc-L-Pro-thio­amide)

Crystals of the title compound, C₁₀H₁₈N₂O₂S, which is an enanti­opure N-protected L-prolinethio­amide, were successfully grown from a tetra­hydro­furan solution. Inter­molecular N—H...O hydrogen bonds are observed between thio­amide —NH₂ and Boc-carbonyl C=O groups, but the thio­amide C=S group is not involved in hydrogen bonding.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.013 Å
• R factor = 0.041
• wR factor = 0.130
• Data-to-parameter ratio = 14.4

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT026_ALERT_3_A Ratio Observed / Unique Reflections too Low ....         17 Perc.

Author Response: Diffractions from the crystal of (I) were too weak to collect enough numbers, even we have used many techniques to increase the number data available (low temperature, Cu-K(alpha) radiationan, area detector).

Alert level B
PLAT340_ALERT_3_B Low Bond Precision on C-C bonds (x 1000) Ang ...         13

Alert level C
DIFMX01_ALERT_2_C  The maximum difference density is > 0.1*ZMAX*0.75
            _refine_diff_density_max given =      1.200
            Test value =      1.200
DIFMX02_ALERT_1_C  The maximum difference density is > 0.1*ZMAX*0.75
            The relevant atom site should be identified.
RINTA01_ALERT_3_C  The value of Rint is greater than 0.10
            Rint given   0.125
PLAT020_ALERT_3_C The value of Rint is greater than 0.10 .........       0.12
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         C9

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           68.23
           From the CIF: _reflns_number_total               2236
           Count of symmetry unique reflns         1377
           Completeness (_total/calc)            162.38%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       859
           Fraction of Friedel pairs measured     0.624
           Are heavy atom types Z>Si present        yes

Author Response: We have checked the number of Friedel pairs is correct.

PLAT791_ALERT_1_G Confirm the Absolute Configuration of C6     = .          S

Author Response: We have checked the absolute configuration of C6 is correct.

   1 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   6 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   4 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: RAPID-AUTO (Rigaku/MSC, 2003); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2003); program(s) used to solve structure: SIR2002 (Burla et al., 2003); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: ORTEP (Johnson, 1965); software used to prepare material for publication: CrystalStructure.

(-)-N-(tert-Butoxycarbonyl)-L-proline-2-thioamide

Crystal data

C10H18N2O2S	Dx = 1.188 Mg m^−3
Mr = 230.32	Melting point = 380–381 K
Orthorhombic, P212121	Cu Kα radiation, λ = 1.5418 Å
a = 6.6413 (9) Å	Cell parameters from 6072 reflections
b = 11.5686 (19) Å	θ = 3.8–67.9°
c = 16.766 (3) Å	µ = 2.12 mm^−1
V = 1288.2 (4) Å^3	T = 173 K
Z = 4	Needle, colorless
F(000) = 496.00	0.25 × 0.03 × 0.01 mm

Data collection

Rigaku R-AXIS RAPID diffractometer	Rint = 0.125
Detector resolution: 10.00 pixels mm^-1	θmax = 68.2°
ω scans	h = −8→8
10145 measured reflections	k = −13→13
2236 independent reflections	l = −19→19
388 reflections with F^2 > 2σ(F^2)

Refinement

Refinement on F^2	w = 1/[0.15σ(Fo^2) + 0.5]/(4Fo^2)
R[F^2 > 2σ(F^2)] = 0.041	(Δ/σ)max = 0.007
wR(F^2) = 0.130	Δρmax = 1.2 e Å^−3
S = 1.05	Δρmin = −1.1 e Å^−3
2236 reflections	Absolute structure: Flack (1983), 885 Friedel pairs
155 parameters	Absolute structure parameter: 0.08 (6)
H-atom parameters constrained

Special details

Refinement. Refinement using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F². R-factor (gt) are based on F. The threshold expression of F² > 2.0 σ(F²) is used only for calculating R-factor (gt).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
S10	−0.0419 (3)	0.4147 (2)	0.38307 (16)	0.0778 (8)
O10	0.4808 (7)	0.6416 (4)	0.3444 (3)	0.061 (2)
O20	0.6917 (7)	0.7078 (4)	0.4420 (3)	0.053 (2)
N10	0.4762 (9)	0.5587 (6)	0.4633 (4)	0.054 (2)
N20	0.0794 (9)	0.6021 (5)	0.4574 (3)	0.059 (2)
C1	0.5506 (16)	0.7192 (9)	0.2856 (6)	0.078 (4)
C2	0.4328 (15)	0.6892 (7)	0.2099 (5)	0.105 (4)
C3	0.7739 (12)	0.7060 (7)	0.2671 (4)	0.097 (4)
C4	0.5007 (15)	0.8440 (6)	0.3068 (4)	0.091 (4)
C5	0.5584 (13)	0.6392 (8)	0.4172 (5)	0.043 (2)
C6	0.3432 (11)	0.4677 (7)	0.4332 (5)	0.049 (3)
C7	0.1194 (14)	0.5001 (7)	0.4265 (5)	0.057 (3)
C8	0.3769 (13)	0.3688 (7)	0.4924 (6)	0.078 (3)
C9	0.4311 (15)	0.4279 (8)	0.5674 (5)	0.097 (4)
C10	0.5537 (12)	0.5324 (7)	0.5433 (4)	0.064 (3)
H21	0.5066	0.7040	0.1624	0.126*
H22	0.3115	0.7328	0.2092	0.126*
H23	0.4017	0.6092	0.2130	0.126*
H31	0.7957	0.6492	0.2271	0.117*
H32	0.8308	0.7774	0.2504	0.117*
H33	0.8358	0.6820	0.3154	0.117*
H41	0.4774	0.8910	0.2612	0.110*
H42	0.6113	0.8741	0.3362	0.110*
H43	0.3839	0.8438	0.3395	0.110*
H61	0.3896	0.4452	0.3819	0.059*
H81	0.2545	0.3271	0.4982	0.093*
H82	0.4807	0.3175	0.4761	0.093*
H91	0.3127	0.4506	0.5950	0.116*
H92	0.5078	0.3773	0.6001	0.116*
H101	0.5292	0.5945	0.5791	0.077*
H102	0.6937	0.5157	0.5423	0.077*
H201	0.1801	0.6486	0.4817	0.071*
H202	−0.0563	0.6279	0.4561	0.071*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S10	0.0479 (13)	0.0712 (17)	0.114 (2)	−0.0097 (16)	−0.0023 (17)	−0.0293 (17)
O10	0.046 (3)	0.081 (4)	0.055 (4)	−0.008 (3)	−0.003 (3)	0.006 (3)
O20	0.031 (3)	0.065 (4)	0.063 (4)	0.004 (3)	−0.001 (3)	−0.001 (3)
N10	0.031 (4)	0.072 (5)	0.060 (5)	−0.007 (4)	0.009 (4)	−0.002 (4)
N20	0.022 (3)	0.059 (4)	0.096 (5)	0.001 (3)	−0.008 (3)	−0.026 (4)
C1	0.092 (8)	0.086 (8)	0.056 (7)	−0.031 (8)	0.012 (7)	0.017 (6)
C2	0.162 (10)	0.083 (8)	0.071 (7)	−0.008 (8)	−0.033 (9)	0.021 (6)
C3	0.093 (7)	0.128 (10)	0.071 (8)	−0.007 (7)	0.049 (6)	0.014 (7)
C4	0.141 (10)	0.046 (6)	0.088 (7)	−0.010 (7)	−0.007 (7)	0.014 (5)
C5	0.027 (4)	0.072 (7)	0.029 (5)	0.011 (5)	−0.005 (4)	−0.013 (5)
C6	0.032 (5)	0.054 (6)	0.062 (7)	0.002 (4)	0.023 (4)	−0.006 (5)
C7	0.062 (6)	0.031 (5)	0.078 (7)	−0.002 (4)	0.023 (5)	0.016 (5)
C8	0.047 (6)	0.094 (8)	0.092 (8)	0.004 (5)	−0.014 (6)	0.030 (8)
C9	0.104 (8)	0.111 (9)	0.075 (8)	−0.022 (8)	0.016 (7)	0.045 (7)
C10	0.049 (5)	0.108 (8)	0.036 (6)	0.008 (6)	−0.002 (5)	0.006 (5)

Geometric parameters (Å, º)

S10—C7	1.629 (9)	C2—H21	0.950
O10—C1	1.411 (12)	C2—H22	0.950
O10—C5	1.326 (10)	C2—H23	0.950
O20—C5	1.259 (10)	C3—H31	0.950
N10—C5	1.328 (11)	C3—H32	0.950
N10—C6	1.464 (10)	C3—H33	0.950
N10—C10	1.469 (10)	C4—H41	0.950
N20—C7	1.316 (10)	C4—H42	0.950
C1—C2	1.531 (13)	C4—H43	0.950
C1—C3	1.523 (13)	C6—H61	0.950
C1—C4	1.524 (13)	C8—H81	0.950
C6—C7	1.536 (12)	C8—H82	0.950
C6—C8	1.532 (12)	C9—H91	0.950
C8—C9	1.476 (13)	C9—H92	0.950
C9—C10	1.512 (13)	C10—H101	0.950
N20—H201	0.950	C10—H102	0.950
N20—H202	0.950
C1—O10—C5	121.9 (7)	C1—C3—H31	111.2
C5—N10—C6	123.5 (7)	C1—C3—H32	111.1
C5—N10—C10	122.2 (6)	C1—C3—H33	106.0
C6—N10—C10	112.2 (6)	H31—C3—H32	109.5
O10—C1—C2	105.5 (7)	H31—C3—H33	109.5
O10—C1—C3	113.5 (8)	H32—C3—H33	109.5
O10—C1—C4	111.6 (7)	C1—C4—H41	112.9
C2—C1—C3	107.8 (7)	C1—C4—H42	107.5
C2—C1—C4	107.3 (8)	C1—C4—H43	108.0
C3—C1—C4	110.7 (8)	H41—C4—H42	109.5
O10—C5—O20	124.4 (7)	H41—C4—H43	109.5
O10—C5—N10	113.0 (7)	H42—C4—H43	109.5
O20—C5—N10	122.6 (7)	N10—C6—H61	108.3
N10—C6—C7	115.7 (6)	C7—C6—H61	108.3
N10—C6—C8	103.0 (6)	C8—C6—H61	109.5
C7—C6—C8	111.8 (6)	C6—C8—H81	108.7
S10—C7—N20	125.9 (7)	C6—C8—H82	112.7
S10—C7—C6	121.4 (6)	C9—C8—H81	110.9
N20—C7—C6	112.6 (7)	C9—C8—H82	111.0
C6—C8—C9	104.0 (7)	H81—C8—H82	109.5
C8—C9—C10	105.9 (7)	C8—C9—H91	109.9
N10—C10—C9	102.7 (6)	C8—C9—H92	109.7
C7—N20—H201	122.3	C10—C9—H91	110.8
C7—N20—H202	117.7	C10—C9—H92	111.0
H201—N20—H202	120.0	H91—C9—H92	109.5
C1—C2—H21	112.9	N10—C10—H101	111.2
C1—C2—H22	108.8	N10—C10—H102	111.6
C1—C2—H23	106.6	C9—C10—H101	110.1
H21—C2—H22	109.5	C9—C10—H102	111.6
H21—C2—H23	109.5	H101—C10—H102	109.5
H22—C2—H23	109.5
C1—O10—C5—O20	3.6 (12)	C6—N10—C10—C9	−9.4 (8)
C1—O10—C5—N10	−178.5 (7)	C10—N10—C6—C7	110.5 (7)
C5—O10—C1—C2	176.6 (7)	C10—N10—C6—C8	−11.8 (8)
C5—O10—C1—C3	58.7 (10)	N10—C6—C7—S10	171.7 (6)
C5—O10—C1—C4	−67.2 (10)	N10—C6—C7—N20	−6.9 (10)
C5—N10—C6—C7	−85.7 (9)	N10—C6—C8—C9	28.8 (8)
C5—N10—C6—C8	152.0 (7)	C7—C6—C8—C9	−96.1 (8)
C6—N10—C5—O10	11.2 (11)	C8—C6—C7—S10	−70.8 (9)
C6—N10—C5—O20	−170.9 (7)	C8—C6—C7—N20	110.6 (8)
C5—N10—C10—C9	−173.4 (7)	C6—C8—C9—C10	−35.7 (9)
C10—N10—C5—O10	173.4 (6)	C8—C9—C10—N10	27.9 (8)
C10—N10—C5—O20	−8.7 (12)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N20—H201···O20^i	0.95	2.10	2.870 (8)	137
N20—H202···O20^ii	0.95	1.93	2.862 (8)	168

Symmetry codes: (i) x−1/2, −y+3/2, −z+1; (ii) x−1, y, z.